pay for unsolicited cards I kept from the Foot & Mouth painters society

When I was living at my old place every year around Christmas I would get some unsolicited cards/calendars painted by foot + mouth artists. They are hideous, and I got them for about 4 years in a row. I think I once paid for them out of guilt or sympathy, but the other times just kept the goods cause I was too lazy to send them back.