Thanks for the post. I just traded in a bunch of games, though most were worth less than $1 (PS2 games, but still painful). The guy at Gamestop did tell me it was only for the DFW (Dallas-Fort Worth) area.
Also, thanks for posting that receipt, Cuksis! I had no idea I could get even $20 for Layton, let alone $30. I don't usually trade in games that I really liked, but I have to admit that Layton probably doesn't have much reply value and the trade-in will almost pay for the sequel.