Can't really recall me ever being ripped off...then again, maybe I'm just too slow to realize it.
On a somewhat similar note, a year ago I went to the local Game Stop in the mall, and by local, I mean a half hour drive away through mind-numbing traffic. I get there, and find a copy of Dawn of War: Soulstorm. And on sale for $20, no less! I see they have an absurdly long line, but a few friends have this expansion, and I'd like to continue playing with them, so I decided to bite the bullet and wait in line.
2 hours of reading random game guides, issues of gameinformer, and the backs of atleast 30 different game cases, I finally approach one of two rather weird looking cashiers (his hair was some sort of half mohawk half ponytail, with a bit of solid snake's mullet thrown in for giggles) And I hand him the case, he rings it up, looks confused, and then tells me "Ummm...we don't have this game."
I ask him how that is possible, to have a complete game case, not a show model mind you, and not the game that came in said case. He shrugs and tells me sorry. I don't hold it against this poor man with horrible hair, he's only doing his job, so I just leave and vow to never go to gamestop again. I'm proud to say I've stood by that commitment.
Seriously though, the fuck do you get a game's case without the game?