Description
In the 1980s, McDonald’s sold a unlimited free refill coffee cup at their restaurants in the United States of America. Anyone who had this coffee cup could bring it back to McDonald’s and get a free cup of coffee forever. There are still a few of these left, and you can find them for sale on eBay. I don’t know if McDonald’s still honors them or not. Most people who work there weren’t even born yet when the McDonald’s unlimited coffee mug was invented. 
