A lifetime iced tea supply
Here’s the thing about buy-one-get-one deals. They are totally awesome. They are supposed to incentivize shoppers to buy more of the product, which they have certainly done in this story. One brand of ice tea was offering a free box of canned iced tea in every box. The loophole here is that even the free box comes with the coupon.

So, one savvy shopper purchased a box of iced tea, used that box to pick up another box for free, and continued this delicious cycle of loophole-exploitation a million times. Luckily for them, the coupons expired after the millionth purchase, so they basically got a lifetime supply of delicious iced tea for free.