My best error was rock band 2 special edition for the wii.
Toys r us had a deal, b1 g1 50% off.
Also rb 2 had a deal of $80 off retail.
The way it worked was,
Bought donkey kong country ($50) and got rb 2. Rock band 2 was $180, it was reduced to half so down to $90. Then $80 off so then down to $10
Walked out with donkey kong country and rb 2 special edition for $60!
Clerk was surprised, said it was such a good deal and he was going to buy it too. He didnt want to let me buy them at first, but I said "Well it rung up that way on the register, it wouldnt of rung up that way if it was wrong"
Walked out the door.. came back in 5 min later and bought another set for $60. I should have cleared out the store, I could of got 10 lol
Ended up selling one RB 2 on CL for $130. Then returned the other games including rb 2 to walmart for a gift card. (ugh frowned upon I know)
Bought an xbox 360 + games. So basically I got a free xbox out of the deal.
Another one, bought 1600 XBox point card from amazon, they sent me two.
Another fun one, 25k in free xbox MSP from call of duty gamestop instant win promo. There was one day where you won every single time, no losses. It was like a 3 hour window.. I could of got more but felt it was enough ( it wasnt! only 1k left)