Steam sell/trade Dues Ex: human revolution, Dirt showdown, and Nexuiz.

I bought a new video card about a week ago and they had a deal where you got Dirt showdown, dues Ex: human revolution, and nexuiz and im looking to trade them for other steam games or cash cheaper then the price on steam of course. Would like to get orcs must die, civ 5 gods and kings expansion and also one more game or just surprise me with a deal and i may like it. This is also my first time trading games on steam wish me luck :)