Where can I sell my gamecube if I don't have an ebay acount?

You're caught between a rock and a hard place. If you know of any auctions in your area try to auction it off. Other than that accept the measly 30 dollars in store credit because you ain't gonna sell that any other way. I'll help you out though. Next time you buy a system save the box. When you want to trade it back in put the wires and the game back in the box, This saves the store in rewrapping and they might give you like five dollars more in store credit (this only applies to gamestop because they are the only ones I know that rewrap used stuff. EB games and Game Crazy doesn't).