http://www.familyvideo.com/catalog/used_games.php
For those without a family video in the area. I dont work for the company anymore so I dont know exactly how they work it out, but I would assume they pull store stock and ship back to the Home office and then buff the discs.
I have a friend that constantly buys things that he needs to use temporarily then returns them. It annoys the heck out of me. Either borrow it from a friend or buy the darn thing and keep it. (Yes, I see that you responded to this in your reply..one of them...somewhere)
Head to your local family video when they arent busy. Ask them if they have any extra cases (they do). They will have tons of DVD cases and some 360 cases, if you arent picky they will probably give you one.
People tend not to return things, extra cases amass in bulk numbers.
Be nice about...