Yes
Yes they need the case
yes
You can use any games you have bought from anywhere and trade them into gamestop to get Game stop in store credits to purchase other games.
No there is only the Gamestop site that tells what Gamestop sells the games for
yeah go to gamestop
it depends on which game it is
No you can't.
GameStop or EBGames.
Sometimes.
Yes
If you trade in a game for another game you normally have to pay them some.
100.00