How much Gamestop trade-in value would I get for these?

Okay, your bound to get at least $100. The reason is cause Gamestop wants you to spend money on their things instead of getting money. So the alternative will be getting less in money and more in a gift card to getting something at their store but you might get a decent amount. Don't get mad if you don't get what you want cause that's their way of saying we just want your money so buy something from us. I had to learn that when getting a DSi