The thrift stores around here never have anything.
I did pick of a boxed copy of Final Fantasy III (VI) for the SNES at a Hollywood video for $10 about a decade ago, when it was fetching $50 for just the cartridge on ebay. All it was missing was the map.
Just the other day I picked up some decent bargains at an FYE, which is going out of business:
Prinny: Can I Really Be the Hero? (complete with soundtrack, the box was open, but the game is still sealed) - $2
Silent Hill 2 PS2 (Greatest Hits, used) - $2
Silent Hill 3 (used, with soundtrack, in really poor shape, but a run through CDCheck says it has no readability errors) - $ .80
Grand Theft Auto Double Pack for the Xbox (sealed and new)- $ .80