Are you looking for a PCI-Express or an AGP card?
The best AGP card you can get at that price would probably be the GF 6800GS (though it may still cost a little over 200$). In case you're looking for a PCI-E card, a 6800GS can be bough for ~180$.
The ATI X800GTO and the X800XL are very good alternatives, but I don't remember any AGP variants.