Low Profile Gaming Graphics Cards

GTS 450 is the cheapest I guess. But buying a decent one for 250 is more valuable than buying a cheap one...

of course there is if you don't mind playing games that were released before 2008

ATI 6570

I have a GeForce GTS 450. I got it for $100 a year or two ago. Still runs most games well. Not high but certainly well...but I'm sure at this point in time you could probably find a more recent card for cheaper. When I bought the card it was a "Shell Shocker" on newegg though.

6670, it's only 50 bucks and can play Dirt 3 on high 1080p 30fps+
Add an A8 cpu and you can do dual graphics which is equal to a 6770(that's what I have), I can play dirt 3 maxed 1080p around 35fps average. If I set it to high I can play 60fps+

GTS 450 or HD 6670