GameStop Help And Game Cost Estimation?

as for how much money you'll get off those games, it's really hard to tell due to the fact that each store generally has a different price for a different game, and that it's most likely based off popularity and how old it is... now, you don't need a credit card or anything like that, when you trade in, they give you credits which is their form of currency, lol... and they put those credits on a Gift Card or something of the type... hope this helps