If you’re my age (and I don’t know if you are, but I sure am!) you never really bought trading cards. Technically, you bought a stick of gum, and they threw in a pile of trading cards. This had several effects, including allowing the manufacturer to claim they were not an illegal monopoly on trading cards but a legal competitor in gum; getting the preferred tax status for foods; and saddling many collectors with finding that decades-old gum has now fused to cards in their previously unopened packs.
I think about this when I see the listing for “Peanuts 2020 Commemorative Print with Wall Calendar“, which is phrased as to convince you that what you’re really buying is this one piece of paper with a Peanuts picture to hang on your wall, and that the other twelve Peanuts pictures designed to be hung on your wall throughout the year are just a bonus. It’s that one picture that you buy to commemorate the strip’s 70th anniversary.