Operation Flashpoint: Dragon Rising is 75% off on Steam, going for just shy of $8. I've heard it's good and will most likely get it, there's a demo if that sounds good.
Recently I've played through the two most recent Tomb Raider games, Bioshock 2, halfway through Red Faction: Guerrilla, Battlefield: Bad Company 2, tried Dark Void (hated it). Most of the games there are newish so they're over the $20 price tag, but all of them (except DV) are awesome.
Oh okay thanks. So, its some kind of an expension for borderlands.
When i first saw it on steam for 9.99 i was like, WOW! this is way cheaper then the original borderlands game that costs like 50bucks and im gonna get it for sure. But now i know what it actually is..
Anyways thanks again
If you want something cheap and fun, take a look at Trine. Try a demo to make sure your PC can handle it, should be fine. It's a short game but it's really, really fun.