Here's some heavy reading for you...

I have been trading for years now and I think that I can almost say that I have seen it all. There's loads of scams and loads of ♥♥♥♥ going around and 99.9% of that is thanks to greed. You can't trust anyone, not even your friends. The only real way to avoid being scammed is by being smart and by not letting your inner greed get the best of you, because if the greed takes over then you can kiss all your stuff good bye and valve won't give anything back. To keep it simple I'll try to stick to the basics, the different sorts of scams so that you know how to prepare and what to look for. I'll also give you hints on how you can spot actual legit people and well, all that you need to know in order to stay safe.
To kick this off I'll start by listing some usefull things that you need to know, some hints, some expressions, a bit of this and that, just keep on reading and if you manage to absorb it all you will thank me later because this will save your ass.

Sorry (not sorry) for the long post, here's a potato.

SteamRep is basically a scammer database, it's not a place where people can collect "rep" or "+rep" comments or anything like that. The site is just for listing and banning known scammers and known alts. If someone refers to his or hers steamrep profile as "clean" then that means nothing, and if someone refers to it as if he or she would be tagged as an admin then you really need to bouble check it your self. Mostly real admins and middlemen don't give out any links to their profiles on steamrep, they want people to check it themselves just so that they know who they are really dealing with.
I have also seen people have an uploaded screenshot of "their" steamrep profile where they ware tagged as admins, that's not what real admins do so if you find someone who has a screenshot of the green tag and all that then it's an impersonator. Steamrep has several different tags, however to keep it simple there's only 4 colors, green (admins), yellow/orange (caution), red (scammers) and last but not least, deep pink (valve employees, they will NEVER contact you!). There's also the normal profile that isn't marked with any color what so ever, this means that the profile has no special reputation however it doesn't mean that the person couldn't be a scammer. You should also know that there's several different tags, most affiliated communities has own tags on steamrep, for example if lethal.zone bans someone on steamrep then the ban will say "banned by lethal.zone" and this also means that the user was reported to that community.
All affiliated and partner communities can be found listed with their banners/logos on SteamReps main site.

The first thing that you need to do is unhide the URL bar from the steam client. This is really simple and in addition to that it's also useful for other things, do as follows:

1. Right click on the steam icon in the bottom right corner of your display and hit on "Settings".
   
   
   
2. Go to Interface and tyick the box infront of "Display Steam URL address bar when available.
   
   
   
3. Copy the entire URL from the steam profile that you want to check.
   
   
   
4. Go to www.steamrep.com and insert the URL you just copied in to the search field (as seen below). Then either hit on Enter or Search.
   
   
   
5. Since I have used my own profile that also means that I have now got to my own profile as seen below. No matter what or who you search you will always find them.
   

When someone says that they have a "clean steamrep" that doesn't mean anything, the only thing that it means is that they haven't been reported to steamrep for any scam yet. It doesn't in any way indicate that the person in question would be trustable. However in 99% of the cases where people refer to their "clean steamrep" they have turned out to be scammers.

Take screenshots of the entire chat, the other users steam profile, trade history, all that you can come to think of. Make sure that all the screenshots are up to "steamrep standards", this means that they should be taken of your entire screen and that they should not be edited nor cropped in any way.

"acc"
Short and simple, "Account".

"alt" or "smurf"
Comes from "alternate account" and it means that a user has one main account and a one or more additional accounts.

"csgol" or "lounge"
CSGO Lounge, refers to {LINK REMOVED}www.♥♥♥♥♥♥♥♥♥♥.com

"tf2op" or "outpost"
Originaly came from Team Fortress 2 Outpost which was the most used trade site back in the days. Nowdays they have also adapted over to csgo which means that you can also buy and sell your csgo items via that site. Links can be found in the end of this guide.

"pc"
Price Check, simple really.

"bp"
Comes from the word "backpack" and it has the same meaning as "inventory".

"bp.tf"
Short name for www.backpack.tf

"MM" or "MidleMan"
A trusted person who helps out in high risk trades, he basically holds on to the items while the money/btc gets moved over to the seller from the buyer. Middlemen are marked on steamrep and when you are dealing with one you must make sure that you are dealing with the real person and not an impersonator!

"tagged"
Mostly used in sentences like "he's tagged on sr" or similar, it refers to a user having some sort of mark, tag on or some sort of notes on steamrep.

"rep"
Reputation, the feedback a user has got from other users after doing trades. Note that this is easy to fake so never trust anyting on anyones steam profile nor any feedback in any steam group.
More about this in the "About rep on steam profiles and groups" section.

"sop"
Good old "SourceOP", a place where people used to have very high standard rep threads and what not.

"someone going first"
This is a term used in high-risk cash trades, since money can't be sent via steam nor any trade offer it means that one person has to "go first" by sending the money or items first.

"sharking"
If a person tells you that an item is worth less/more than what it actually is so that you would make a loss in a trade and he would gain on it.

Personally I would say that you shouldn't even poke at these with a mile-long stick, most of them are probably rigged (take CSGO Lotto as an example) and if they are not rigged then you will most likely get an addiction that will ruin you. You should also know that there are loads of fake gambling sites that come and go and there's even more scams revolving around fake gambling sites.
If you lose something then valve/steam won't give anything back. Also, if someone suggest to you that you will win loads if you bet with him/her, basically rig the site in your favour then you will basically be on the same level as the scammers.

Also please read this: http://node2.projectplanet.cn/@store.steampowered.com/news/22883/

• Check the user on SteamRep.
  
• Check how far back the users history goes on SteamRep.
  
• Check if and how much the user has used trade sites (csgol, tf2op, tf2tp, d2l), this can be done via the research tools
  on SteamRep.
  
• How old is the account (can be seen on steamrep).
  
• How many games does the account have.
  
• How much playtime has those games have.
  
• How much items does the account have in its inventory (all, games, cards, csgo skins, tf2 items and so on...)
  
• What level is the profile.
  
• How many friends and steam groups is the user in.
  
• Is there "proof" of other cash trades on the profile, like screenshots and so on (if yes then those are all fake!).
  
• Is the user a member of any "+rep" or "rep boosting" group (if yes then remove and block the guy).

Imporant notes

People these days tend to buy old accounts so even if the account has several years of age and yet nothing is stored in the accounts history on SteamRep then you are most likely dealing with a bought account. This means that you CAN NOT trust the person behind that account. The same goes for high leveled steam accounts, scammers these days tend to boost the level up to +50 (even +100 from time to time), farm fake rep, add content, make themselves look legit and so on. You can mostly spot these if you do a combo check on account age + recorded history on steamrep + trade site usage. These can also not be trusted, they are made to look legit just so that you would think that they actually are legit and so that you would go first. It's also worth noting that some old accounts that have been sold may have historical data on steamrep from before the account changed owner. Mostly in these cases you can see that first the account had friends and then all of a sudden it had literally 0 friends from and then after a while got more and more friends again.
If you are unsure about a user then you can always suggest to use an official middleman from SteamRep, if the person you suggest that to claims to have either bad experience of those or if the straight up refuses to use a middleman then just walk away and look for an other person to trade with.

When you do trades for example via PayPal or direct bank transfer you can add notes to the transactions. There's most likely other ways to send money and add notes but just using these to as an example because these are the most common ones where notes can save you.

When you receive money you should always tell the buyer to add the following notes:

Seller: *steamID64*
Buyer: *steamID64*
Item(s): *list or links to each and every item on csgo.exchange*

If some of these things don't add up with the trade at hand then you are likely dealing with someone who would is about to scam you. At this point it's best if you just refund and call off the trade.

If you want you can make notes to yourself so that you'll know if the same person tries something again but with an other steam acc.

Pretty much everyone who trades and/or plays CS:GO have loads of "+rep" comments on their profiles. For some reason (which I don't understand) people give "+rep" comments to other players profiles as a sort of respect or something. People then also of course claim that they are trade related which supposedly makes the person in question look "trustable".

Steam Profile comments

There's only one person who can manage these and that's the user who owns the profile. This means that if someone gives negative feedback (-rep or what ever you want to call it) then the user can just remove it and block the user who gave the feedback, this way no one will ever know that there was a negative comment there.

Steam Group comments

Almost the same as steam profile comments however in groups there can be several moderators and administratos who take care of stuff. It's very common that scammers make groups where they add their alts and then boost up the members and rep threads comments with the help of one of many "rep 4 rep" groups out there. Even if a group would be legit there's no way in hell for the admins nor the mods to actually know if a rep thread is legit or not, they can't check if the comments are made by real people or just alts.

Ask yourself, how can you trust either of these two above!

Web sites are different than this, if the site is legit and well designed with capable staff then that also means that they won't let any scammer make a rep thread nor leave a comment. Sites also keep alts away and actually help their users if there's any issues what so ever.
One other important thing with sites, they never let their own staff members have any rep threads hosted on the site, that would render their rep threads as useless as profile comments.

Trades like this can come at any time, literally. Some random person wants to trade some of your items for some of his. However the other person will tell you that he has seen items "bug out of trades" or what ever (there's loads of different stories) so he'll ask you to send the items to one of your friends who you trust so that the other person can see that the items won't go anywhere. At this point the scammer will use an other account to impersonate you (make his profile look like your profile) after which he sends a trade offer to your friend asking for the items back. Since your friend most likely won't notice anything he'll just accept the trade right away - so the scammer gets your items.

There's also a few out there who claim to be valve or steam item checkers, or even some sort of people from valve who check stolen items or what ever. Some of these guys will even say that they will ban you or lock your account or what ever, it's all just lies and slander.
Some of these who claim to be valve employees are in a "NON-STEAM GAME" that is usually named to "Item verificator", "Item database" or something similar. Here's a perfect example of that (this can also be seen in another screenshot here in the guide):


...and then there's also those who upload "Artwork" or "Screenshots" that are supposedly pictures of their certificates and what not, all these are as fake as anything can get. If check for example the listed email adr. (example below) you'll notice that it ends with @gmail.com - why would someone who works for valve use gmail?
The "certificate" below is something that I took from a scammers profile, however I have added the watermark on it so that it wouldn't be that easy to just grab it from here and use it for scamming. If you anyhow read the text and use your head with a hint of logic you'll see how full of s**t it is.

--- Valve employees and steam admins/mods are never in contact with other steam users ---

There's no way in the world to send money to an other users steam profile, the only way to add money is via one of some card, paypal and such or alternatively a wallet code (that can for example be bought from GameStop). 99.9% of those who offer wallet codes are full of it, don't trust them and never trust any profile comments. some people say that they will give you half of the code before the trade and the 2nd half after the trade. However they never give the 2nd half and if they do then the code is anyway just some random letters and numbers that they have mixed to gether. Some people also sell games that come as codes which are somewhat easy to find, however it's very risky. You will always have to make sure that you the guy you are dealing with is legit, valve won't give you any refund nor antyhing else if you get scammed like this. I would simply just advise you to NEVER buy any codes what so ever from any normal user, the only places I would recommend to buy from is stores and bundle sites.
If you however decide to trade something for wallet codes then make sure to use an official middleman from SteamRep.

List of active middlemen on SteamRep: www.steamrep.com/list/M

When dealing with paypal you need to be very careful and read everything that paypal has to say. If you sell something for moeny over PayPal then you should not for what ever reason accept any money that has been sent as "family and friends", since you are selling items you should get the money as "services/goods". Personally I would recommend for you to send an invoice to the buyer, that way you can add all notes that are needed (buyer steamID64, seller steamID64, items involved). After each and every trade done with PayPal you will need to take screenshots of the entire chat, steam profile and trade history. All this can be used if the other guy tries to chargeback the money later on and if there's a disputer or chargeback then you will also need to add all the screenshots to the scam report that you should file on SteamRep or one of its affiliated communities.
PayPal invoices can also be abused by the buyer, he can send you an invoice and then instantly mark it as paid to make you think that they have paid you. You won't get any money to your balance tho and if you say about that to the buyer then he will most likely tell you that it's a glitch or delay in PayPal - this is a lie. If you click on the invoice to check the details you will see a huge text "INVOICE" in the upper corner of the page, the scammer will most likely also have added some custom notes that make it look like an actual payment. If you come across anything like this then you will need to take screenshots of everyting and file a scam report.

This means that a person (or bot) is trying to get your personal details, login credentials...basically what ever details they can abuse in order to get to your money. A while back there was also loads of fake steam sites that were giving away games for free, all you had to do was pick a game from a list and log in to steam.

Never click on any links any one sends to you! Never download anything that anyone sends to you! Never let anyone take remote control of you computer!
Always check the URL letter by letter before you log in with or to steam.

Fake cash rep refers to users farming literally comment saying that they are good with cash trades and/or steam wallet codes, sadly there's loads of steam groups out there dedicated for ♥♥♥♥ like this. Profile comments are the easiest thing in the world to fake, a user can delete literally all and any negative feedback and well, farming fake comments is like childs play. However some communities like Lethal Zone try to warn users about those who are farming fake cash/wallet rep by adding caution tags complete with notes on SteamRep to those who are farming the fake rep. There's also people who do "legit" trades for a while using an automated bot that for example buys and sells keys, this generates rep and that rep can sometimes also get abused by the bots owner. Therefor I would recommend to stay far away from new users who run bot services.

The topic pretty much says what it's about, misrepresenting the items by saying that they have properties or functions that they don't actually have (is the same as scamming) or that the price is completely different than what it actually is (aka "sharking").
Sharking isn't really a scam, it's abusing a persons greed and lack of knowledge about research tools (like google). Even tho those who are sharking on a daily basis will end up getting banned from all sites and servers eventually simply because it's very bad ethics. You can post reports about this to some of SteamReps affiliated communities (check ther investigation policies to see who handles sharking), however remember to include as much evidence as possible.

Example - Trade from CSGOL

Sadly there's loads of "users" (bots) that posts trades like this, they advertise a "Factory New" item and that anyone who's interested should send them a trade offer fast. The thing is that once the trade offer is sent it will get accepted by the bot instantly which means that there's no way to cancel the trade when you notice that something is wrong. They post a trade when they have the Factory New item and once the trade is posted they move that FN item over to another account and replace it with the same weapon but with a way worse quality.

The trade on CSGOL...


...open trade offer - all looks 'ok' until....


...you hover the mouse over the item and see the item quality.

There is no such thing, it's all just lies and bulls**t. No items need any sort of checking nor verifications or any other stuff like that. Scammers just pose as valve employees and tell you lies so that you would then give them your items. Also Valve has no "item verification software" nor any other ridiculous stuff like that. Below is a perfect example of scammer who has just added a non-steam application to steam, renamed it to "Steamworks I Item Verification".

(screenshot taken in Chrome using the SteamRep checker plugin, link in the end of his guide)

As you can see, it even says "In non-Steam game"...why would something that supposedly be steams own software be a "non-Steam game"?
Now take a look at the profile description. No valve employee nor steam administrator/moderator will ever contact anyone. Speaking of which, here's a list of the actual steam mods and none of the steam mods are related with SteamRep in any way.

I can't say for sure how people come across these but it's good to know that there's stuff like this out there too. Simple example of one case that I had to investigate: A guy gets loured in to gamble on a site because the sites owner has rigged the game for him, alternatively it can just be a "random user" who claims that he knows a glitch or what nat. All stuff like that is just lies and slander, also if you agree to rig a game then you are as good as the scammers which means that you will also get tagged on SteamRep.

This basically means that a person has bought something with a credit card and then claimed to the credit card company that the card was stolen, this results in the payments being cancelled and all the items that have been bought gets revoked. This applies for games (mostly new and high-value games) and basically everything that can be bought in or via steam. If someone offers to gift keys to you in-game (Team Fortress 2) then you know that the keys will get revoked and you will be warned or even suspended by valve. You should never accept any items that get gifted directly from the store and when you trade for new games or games that has a high value then you need to make sure that the guy can actually be trusted and that he has bought the games himself (if not then I would recommend not to trade with him).

Tools

SteamRep Checker (browser plugin)

Shows if people are marked on steamrep or not.
Chrome[chrome.google.com]
FireFox[addons.mozilla.org]

Steam Inventory Helper (browser plugin)

If you do massive trades then it's easier to manage the trades with this tool rather than clicking million times just to make one trade offer that will anyway give an error. Official steam group.
Chrome[chrome.google.com]

Links

• SteamRep (forum)[forums.steamrep.com]
  
• Lethal.Zone (trade)[trade.lethal.zone]
  
• Fortress of Gamers[forums.f-o-g.eu]
  
• Skial[www.skial.com]
  
• SourceOP (forum)[forums.sourceop.com]
  
• Big Bang Gamers[www.bigbanggamers.com]
  
• Harboon Gaming[forum.harpoongaming.com]
  
• Outpost (TF2, CSGO and Dota 2)[tf2outpost.com]
  
• TF2 Trading Post[tf2tp.com]
  
• TF2 WareHouse[www.tf2wh.com]
  
• Bazaar[bazaar.tf]
  
• Backpack[backpack.tf]
  
• Scrap[scrap.tf]

If an offer sounds too good to be true, well, then obviously it's not true. Don't do anything too fast, use your brain and always remember that "slow n steady wins the race". Never trust anyone "by default" based on profile comments, profile level or "proof" of previous transactions (screenshots and what not on the steam profile profile). Don't let your inner greed get to you.

If I have missed of forgot something then feel free to comment here or add me n tell me what my slow and derpy brain has forgot...

Here's a list of the stuff that has been either suggested by other users or things that I have thought of that will get added. All the things listed here will get added to this guide once I get some spare time to actually create the content.
If you have a good suggestion that I'll publish too then I'll also of course give you credit for it.

• SteamGifts and SteamTrades section as suggested by BlackSpawn

14.2.2017

Added - "Updates to come"

12.12.2016

Updated - "Item misrepresentation and sharking"

9.12.2016

Updated - "Fake Middleman & Impersonation "

3.11.2016

Updated - "Useful links and tools"
Updated - "Common terms and expressions"
Added - "About rep on steam profiles and groups"
Removed - "WIP"
Updated - "Intro"
Added - Potato
Updated - General look and layout of the entire guide.

28.10.2016

Added - "Always add notes to the transactions (if possible)"

27.10.2016

Added - "Item verification and item checking"
Updated - "How to search on SteamRep"
Added - "Update log"