Yeah, it's retarded. You should never sell your games/systems at the big-name game stores like Gamestop and stuff, they rip you off like crazy. It's how they make their money, though. I did it with my old PS2 games that I don't play anymore, only because I didn't feel like eBaying them. Just eBay your Zelda, not only will you get more but you'll make some kid happy. >_>
You could try pawn shops, but they rip you off too.