ali.bassam wroteHey xdrone, what I saw on the Steam Market was more of Game Items rather than real games, am I wrong?
You're right, the steam market consists of in-game items from dota2, TF... The main way to buy on steam is from the game's store page.
As for your first question, I believe some of these sites like the one you posted can be legit. But I'd rather wait for steam sales (Summer sale is near in like 2 months or maybe sooner) or humble bundle to get the games and at cheaper prices. Since the other sites are like some sort of hub for people to post their game keys and sell them at cheaper prices (= scamming is possible). Hope this helps.
Edit: g2a.com .. I've tried this website a few times to buy some keys and stuff without any issues, but they were minor transactions.