Actually, the song dates from about 1956, and was originally recorded by the Chips, a doo-wop group from Brooklyn, NY. The original version has turned up on a number of novelty compilations, although I don’t think any are currently in print.
My take is, it’s just a guy trying to make a joke out of the fact that he’s got no money to buy some food. The tag is: whattaya want for nothin’…a rubber biscuit?