I believe these core can be used in a cheapaz comp :
Nvidia :
GF108/GF117 (but it's 40nm vs 28nm)
GK208/GK208B
G92/G92B
AMD :
Cape Verde
Oland/Mars/Opal
Intel :
Any HD graphics from a particular generation/socket
The G92/G92B is hit or miss, sometime price are really crazy and sometime you can get one for really cheap but for all other, there is enough different card/reference to bench, even on laptop (for these, CPU are old and cannot compete with recent one so maybe try to have at least 2/3 bench with GPU score only ?)