Anyone remember the record clubs? You'd get a mailing, offering a subscription service from one of the major record labels. I specifically remember Columbia House, but there were others. You would accept the subscription offer by return mail, agreeing to buy a certain number of records within a given amount of time, perhaps a year. Then you would receive a shipment of record albums featuring some of the better known performers that month, along with some clunkers. Keep what you want, send the rest back. Same deal the next month, and the next, etc. They were banking on the pain-in-the-butt factor involved in shipping record albums back, and that you would forget to do so by the deadline, resulting in an invoice. It was also a way for recording companies to get rid of stocks of lesser known artists. Books were also sold this way, among other things. Today, it's razors, gourmet ingredients, and surprise boxes. Same basic concept.