Not strictly monster mag, or movie monster related, but the kind of thing that appeals to monster mag fans.
This classic ad was, no doubt, seen by every kid who read a comic book at the time. Commonly known as the Moon Monster ad, or more accurately, the Monster Fan Club ad. Another one of those ads that promised something amazing for only $1 (plus postage) and, once again, you didn't get a lifesize statue of a movie monster, or even some cheap Topstone masks. All you got was a pile of paper.
Thanks to prof. grewbeard for the scan of the badge!
Here's the ad, circa 1970.
And here's your "Life size reproduction of a Movie Monster!" A 74" x 27" two piece poster, that does look a little bit like the demon in "Curse of the Demon".
And your "12 4x5 glossy photos of your favorite monsters!" (And no, they're not glossy!)
Your "Monster (or is it "Horror"?) Fan Club membership card and (1¼") badge!"
Your "Official Club Bulletin" (featuring news of the 1968 Karloff film "The Crimson Cult").
And lastly, your "Extra Bonus! 3 Monster Masks"