You can get 8800GS 384MB for a good price
Newegg.com - EVGA 384-P3-N851-AR GeForce 8800GS 384MB 192-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Desktop Graphics
Newegg.com - EVGA 384-P3-N851-AR GeForce 8800GS 384MB 192-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Desktop Graphics