Honestly, not that much, probably like 5 a game, the only one that is sorta rare would be Mega Man 6 which you could get up to maybe 20 for it. NES games arent worth that much in general, I just decided to keep all mine.
Alright I have two quick questions. First Is there a way to change the color of my font on my PS3 because some backgrounds are too white for me to see text. Second when hooking a PS3 to your comp for sharing of files, what has to be done on the PC to allow for transfer. Thanks.