To me, this is the cheapest card that looks tolerable:
http://www.newegg.co...N82E16814131173http://www.newegg.co...N82E16814102814 (Significantly better, but costs more)
For less money than that, its pretty much just Nvidia's FX series (worst graphics card series ever released) and Nvidia 6200's which are horrible.
Depending on where you live, you may want to try ebay'ing a card.
http://cgi.ebay.com/...=item19b753ff0dThis card is nice, I owned one myself. It's also a VIVO version, which are able to flash to X850XT or X850 XT PE if you're an enthusiast. This will unlock more pixel pipelines, increasing performance.