Few details you need to know to don't get scam
they have no cash rep in dota2trader and csgorepthread
if you check their comment (most of them ) have tons of rep in few days(look at dates)
always check offer trade to find out he is already ban or not
always check their ♥♥♥♥♥♥♥♥♥♥ profile and see how amny item they buy with cash you find out they buy anything
only possibilty if some one buy any item is he buy with rate of .6 or less
if anyone offer you more than .7 market price he is scammer (in most case) even if he pay first with paypal
if they use private profile or trade account they are scammer
if they advertise with another account for their main account they are scammer(dont add me here add me there .. )
if you wanna use middle man do go for it fast just search you how many pple scammed by fake middle mans so you need to talk to some one first to avoid get scammed search in reddit ask there to help you to use middleman
anyway dont think you are smart and you dont get scam
if you go first you always can get scam
So guys best way is use new sites for doing reall money trade like opskins.com
dont waste your items to sell soem one with huge price
never forget opskins.com

One thing you sincerely need to know is many times you will read a trader's account you may see he or she has alot of + Rep "Good Trader"
Make sure you do some research about this Steam User!!
Keep in mind not everyone on steam is a scammer
If he or she is saying something like
"Oh you don't trust me look at my account i trade like this alot"
(Hate to tell you) but its Fake The main reason for the fake +rep in the scammers account is so they may appeal more trust worthy meanwhile the fake +Rep can be from either victims not knowing they are going to be scammed. Or people giving one another fake "+Rep"
Look at the reasons he's trying to give so you trust him

In this scam you will have some one approach you wanting to trade there knife. However not for your knife but for this special and extremely rare skin that you have never heard of. Meanwhile the scammer will tell you this item is "worth alot of money" and due to the fact that its so rare you will not be able to find it on the Steam Market place. Most of the time when this scam is trying to be pulled they will tell you many times its near the same value of your knife and you have nothing to worry about cause you making your money back will easy.
After you are convinced this trade is great and all they will tell you at the very end they don't have the rare item that in fact they had been scammed of the item he or she wishes to trade you for it and asks for you to friend them and trade your knife to him to retrieve the rare item by trading your knife to them. Meanwhile it was the scammers alternative account and you are blocked by both with no means of getting your knife back...
this

Within this scam you will be spammed by a user with messages about an amazing trade offers and therefore send you a link to a miss spelled proflie page or it can be a screen shot which is filled with Virus filled software to hack in your steam profile and take your cs go skins...

In this scam someone with a good amount of hours invested into CS GO will add you asking you if your interested in joining their Counter-Strike Team cause they need one more to make a full team. When you go to join the team the user will tell you they only use TeamSpeak to chat and you must have it to be on the Team. When your ready to join the teamspeak server the link they send you will have a virus that can see all your computers information and including your steam account. After the user has access to your account you will no longer have any skins due to they fact that they traded it to themselves and your thin soon blocked if you ever get your account back that is...

This scam is a fairly new one. The scammer randomly adds his victim (usually through steam groups) and tells him he is the owner, moderator or co-owner of a new gambling site. Since he is apparently not allowed to play on there himself, he´ll promise his victim to let him win on the site in exchange for a profit participation. Since this site can mostly be manipulated by the scammer himself he´ll choose a winner for the next draw/round and tell his victim the name to proof that he can actually make anyone win. Once the victim deposits his skins on the site, they are either gone, or new skins cant be withdrawn.