The Black Stamps giveaway, mentioned in this Double Bill pressbook for The Gorgon and The Curse of the Mummy, didn't really have any purpose. S&H Green Stamps, given away by supermarkets (I recall my mom pasting all those stamps into her saver book, filling it page by page) would allow you to trade them in for something desirable at the redemption center. There was no redemption center for Black Stamps. But being a horror movie fan, I'd have died to get them anyway. Natch!