Lockerz is what made a lot of users on my site (pikagame.com) fanatics about free stuff. They do send out prizes however the process is somewhat shady, as they

Lockerz is what made a lot of users on my site (pikagame.com) fanatics about free stuff. They do send out prizes however the process is somewhat shady, as they have a limited quantity and the prizes are only available at a certain time/day (kind of like Woot). It might get you something but honestly it's probably not worth the time.