This reminds me of the pudding guy, yes it really did happen. A quick search will verify this.
Things took a strange turn in the Phillips household last year when David, a civil engineer at the University of California at Davis, turned to his schoolteacher wife Cindy and said with disquieting urgency, "I'm going to go to the bank and get some money. We have to buy as much pudding as we possibly can."
Phillips had stumbled upon one of those frequent-flyer promotions in which airlines team with credit-card companies and other partners. The deal, since withdrawn, was this: buy 10 Healthy Choice products and get 500 miles--or 1,000 miles for purchases made before June 1999. Phillips tossed soup and popcorn into his basket like an end-of-the-world fanatic, but went apoplectic when he saw chocolate-fudge pudding cups at 25[cents] a pop. A mere $62.50 worth, he quickly calculated, would buy 25,000 miles.
"Being a geeky engineer, I came home and put everything into a spreadsheet," says Phillips, 35, who had spent five years saving miles to fly Cindy and himself to Europe. With this deal, they could take their two daughters along, and so within days he had cleaned out every supermarket chain in the Sacramento area, unable to stop himself until he had bought practically enough pudding to fly business class to Mars. In the end, he had spent $3,000 on 12,150 cups of pudding, accumulating 1.25 million miles. (He also donated most of the pudding to charity, qualifying for an estimated $800 tax break.)