Blue Chip Stamps. Department and grocery stores used to outsource their customer loyalty programs to companies like Blue Chip Stamps. You’d make a purchase and get a certain number of “trading stamps.” Once you’d collected a bunch, you’d trade them in for something cool from a catalog—there’s an episode of The Brady Bunch where the girls want to use the family’s stamps on a sewing machine, and the boys want a canoe, for example. In 1970, when Buffett bought up Blue Chip, the company was worth $126 million. Today, barely a handful of stores still use Blue Chip, and they make around $20,000 a year.