This is not a postcard, but rather an arcade card, which were sold in vending machines at places like fairgrounds and carnivals. Often they were the prize in some mechanized test of strength or skill. The cards are about as heavy as pasteboard, and are blank on the back.
Arcade cards from later eras featured everything from pin-up girls to movie stars to stills from TV episodes. Earlier cards from the 1920s and 1930s, however, generally featured comic (and usually slightly risque) sayings and drawings.