I'd say only two choices. $200 for the new Asus Ti4200 card that has tv out/DVI/video in functions if you want that kind of stuff. If you are only looking for 3d performance go get a 128MB Radeon 8500, it's $150 or less. If you really want to save money get a 64MB Radeon 8500 for $91.50 (shipping included) here:
<A HREF="http://www.newegg.com/app/viewproduct.asp?description=14-102-226" target="_new">http://www.newegg.com/app/viewproduct.asp?description=14-102-226</A>
Newegg is a very reliable company I suggest you do all your shopping there.
Ordinarily I would be hestitant to recommend only a 64MB card to you since future games will use more and more memory, but since you want to save money that is the cheapest card you can buy with good performance.
1° of separation between my monopoly and yours. That's business with .NET