Most places, if not all, give store credit, so they arent losing money on anything. You have to spend the credit at their store. So basically you are just swapping game for game, etc. Plus, most stores will only give credit at the lowest price your returned game has gone for in a set period of time (month or two). So if you got it as a gift, you should ask to trade it for another, no harm there. As for returning for cash, or buying clearance games and trying to get more credit than you paid for, thats just wrong and set for another story.