Cereal Killer
Back in college we found a loophole with coupons at Kroger for General Mills cereal. If you bought 4 boxes of cereal each box was a dollar. But if you did the self checkout you would be printed out a coupon for $4 off your next purchase.
We used the loophole to buy about 300 boxes of cereal. We only spent $12 on all of it. We would’ve spent less but we had to go to another Kroger once the manager got wind of us.
We kept around 20 boxes for ourselves and donated the rest to the local food bank. They were so excited when we showed up with three vehicles full of cereal. Totally worth the $12 and all the time it took.
Story credit: Reddit / RoiVampire