Look up Archies joke book #66 in the O-street guide the variant price edition.
Archie comics were being test marketed with both 12c and 15c cover prices in the early 1960s. I sold an Archies Laugh #144 comic from 1963 with a 15 cent cover price on it about 2 years ago. I was blown away when I looked at the title page and it clearly stated 12c per copy inside the comic. I had a dealer check his stock and all 4 copies of his archies laugh #144 had the regular 12c cover price on them as most all archie regular size comics have from 1962-1969.
Wow! imagine that 15 cent cover prices on archie series comics way before they went from 12c to 15c in late 1969. Any other archie issues out there that are 15c cover vs 12c and not listed in the guide out there folks? Check yours they are rare to find. Let me know if you discover any of them.