In 1999 a civil engineer named David Phillips from Davis, California spotted a promotion while grocery shopping.
Healthy Choice was running a deal: mail in 10 UPC codes from their products and get 500 frequent flyer miles from the airline of your choice. If you sent them in before the end of May, they doubled it to 1,000 miles per 10 codes.
David did the math.
The cheapest thing that qualified was single serving Healthy Choice pudding cups selling for only 25 cents each at a discount grocery chain. So for every $2.50 spent, he could get 1,000 miles.
He went all in.
Over the next few weeks he and his mother in law drove around to ten different Grocery Outlets in the Sacramento area and bought every single pudding cup they could find. In total he purchased 12,150 cups for about $3,140.
He stacked them floor to ceiling in his garage and living room, then mailed in all the UPC codes right before the deadline to get the double miles.
When the certificates arrived he had earned 1,253,000 airline miles.
He donated almost all the pudding to food banks and claimed a tax deduction on top of it. The miles were mostly put into his American Airlines account, which pushed him over one million miles and gave him lifetime Gold status.
That stack of miles was worth tens of thousands of dollars in flights. He and his family used them to fly to over 40 countries over the next several years basically for free.