Hi all, some days ago I found a web for Games. (http://www.tremorgames.com)
On this web completing offers, play a game and complete Achievement, Refer friends, etc earn coins. With this "coins" can buy Steam Games, Steam Trading Cards, BitCoins, Amazon Gift Card, etc.
Then I Leave a Video:
http://www.youtube.com/watch?v=9_dcwz_FO0A
This Works, I buy 2 games today.
Register with my Ref:
http://www.tremorgames.com/?ref=42667
When you buy a game, you should go to your profile in the section "Items" we will send a CD-KEY. With this CD-KEY we can activate on Steam.
When you buy a Steam Trading Card, in the section "Items" on your profile you have to wait the approval, then you recibe your "Steam Trading Card" on Steam.
I hope they work.