This Fonz T Shirt ad appeared in Justice League of America No. 138 published by DC comics in 1977.
This is an issue that I may have gotten as a stripped comic for a penny. Back then, unsold comics were returnable to the company that distributed them to newsstands and convenience stores, but the distributor didn’t actually want the old comics back. If a store had left over comics, they could tear the covers off and send them back to the distributor for credit. The rest of the comic was supposed to be thrown out, but a lot of sellers offered these stripped or coverless comics for a fraction of the original cover price, and they did so out in the open. It was all profit by that point. Somehow publishers and newsstands made money selling comics back then. I love comics like this because it takes the collectors’ curse off of them. They can be thrown around and enjoyed for the trash entertainment they were meant to be.