英语笑话:Until They're Free（直到免费为止）

Deciding to do some back-yard landscaping, my father-in-law went to the brickyard to buy quantity of brick. When he asked the salesclerk about the cost, the man replied. "The more you buy, the cheaper they are."　　"'is that so?" said my father-in-law." Then just keep loading them on my truck until they're free.