Have you seen a shirt with as ugly a picture as what was on the shirts in this episode? I have not.

They do remind me of bubble gum trading cards that had that type of art on the cards.

http://3.bp.blogspot.com/-CFTiDN7xr4Y/UmGR6X0CAzI/AAAAAAAASfE/4PQ6ElcMvSg/s400/Leave+It+to+Beaver+Sweatshirt+Monsters+Window+Display.jpg

And $3.75 for the sweatshirt. Wasn't that like a week's worth of groceries back then?

One thing that puts these graphics in perspective is that back at the same time there was a guy named Ed "Big Daddy" Roth who popularized gruesome caricatures as part of the hot rod culture.

Do an image search for "Big Daddy Roth" , "Mr Gasser", "Drag Nut", or "Rat Fink" and you'll see what inspired Beaver's sweatshirts

If they weren't sold anywhere, those shirts must have kept the costumers busy.

Right, I remember those Funny Car gross artwork pictures too. I also had a set of cards, and also stickers with that type artwork, here's an example by Ed Roth, no less:
https://i.pinimg.com/originals/16/3b/15/163b153e82f420e7b25f643858c0b7f8.jpg

And here's my favorite mechanic working on my car:
https://cdn.wallpapersafari.com/22/53/UfDk1v.jpg

Now you can buy your own Monster Sweatshirt (https://www.threadless.com/shop/@mitchoconnell/design/leave-it-to-beaver-monster-shirt-beaver-version/mens/sweatshirt/sponge-fleece?thref=google_shopping&gclid=CjwKCAjwiLGGBhAqEiwAgq3q_oGlBnu0uKLKFcnjnvB27Vjte9SFUI9I-eTDx7cjYs71uTw2Flq1GBoCa7YQAvD_BwE)...