4LOOT will let you be able to win Facebook credits. You can use the Facebook credits for your favorite game on Facebook
http://www.4loot.com/?id=291528&src=em (http://www.4loot.com/?id=291528&src=em)
you need a Facebook account (DERP)
The thing with this is, 4Loot is a search engine (they use Yahoo! >:I) and when you search, you can earn coins which you can exchange for FB Credits.
I've used it for a while now, and it really works. =3