CVS has a deal where you earn $5 gift certificates for every two Rolaids or Listerine PocketPacks a customer buys. These items cost about 99 cent each, meaning a profit of $3 per transaction. The deal is unlimited. After a two day wait, you can repeat the process, using the certificates from before to buy the new Rolaids and Listerine, repeat, repeat.
One coupon hound found that her store had run out of the items. So she whipped out the ones she previously bought and bought them again. Call it shoplifting into the store.
It will certainly be exciting for the store manager doing inventory when he discovers he’s sold 1500 of his 1000 Rolaids.
(Thanks to Joe!)