Trying to sell PS2 and gamecube with games, how much would that cost? enough for ps3?

You wont get anything from gamestop it wouldn't even be worth it. Have a garage sale lol, notify friends and family of the sale, go on craigslist or a local advertising on the internet. You'll get alot better responses and people willing to pay a little more. you could even consider a local pawn shop but they wont offer much either but it would be better than gamestop