A crook decided to break into the counterfeiting business. To ensure success, he decided that he would only try to pass his phony currency in the most back water towns deep in the heart of hillbilly country, figuring that most of the poor and simple folk who lived there had never seen denominations of even modest size.
He then strikes upon the idea of printing $18 bills. After all, if the Treasury Department caught him, then he could claim that he was just goofing around: nobody would ever cash an 18 dollar bill.
He loads his wallet full of his contraband currency, and heads to swampy country. He saunters into a general store, picks out a soda, walks to the counter where he is met by the clerk. The clerk says "that will be 50 cents". The crook whips out his $18 bill and says "Can you break this for me?"
The clerk responds, "Sure, do you want 2 $9's or 3 $6's?"
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