In 1974-1976, the folks at Marvel Comics ran a promotion which was amazingly successful when you consider that it hinged on getting devoted Marvel readers to deface their comics. It involved something they called Marvel Value Stamps, which weren't really stamps. They were just little stamp-like pictures of various players in the Marvel Universe. You cut them out of your comics and pasted them, using your own paste, in a booklet. There were a hundred in the first set and once you'd maimed and ruined 100 perfectly good comic books and glued the clippings into the booklet, you got…well, almost nothing.
There was some sort of 10% discount on some Marvel merchandise but in order to qualify for it, you had to mail in this booklet you'd spent months compiling with a stamped, self-addressed envelope so they could validate it and send it back to you with your discount coupon, and I don't think many fans bothered. Many probably felt foolish that they'd bothered to collect all 100 "stamps" at all but a lot of kids did. For more on this shameless bit of funnybook hype, consult this website which displays all the stamps plus vital info on the whole silly program. Especially read the page entitled, "How Marvel Convinced Us To Cut Up Our Comics."