A copy of Super Smash Bros. Brawl from Gamestop. I went there one day to buy used since I didn't feel like spending much. Store Clerk says it was $44. USED. Which is crazy for a used copy that was made three years ago. Being the dumb customer I was, I bought it anyway. Come home, play a few matches, and game craps out on me for like 17 minutes (Which I can't finish all-star mode in that time). Going back to the store a few days later, I ask for a working copy. clerk tells me they only got 2 used copies, with the other one in my hands. I go home with the other copy, and it was even worse than before. Now the game will stop working after the cation screen.
And the lesson for today is to go back and get a refund for stuff that don't work otherwise suffer with an expensive coaster.