Who said 'there is no free lunch'?

Nobel-prize winning Chicago-school economist Milton Friedman is famous for saying, "There is no such thing as a free lunch." Sci-fi novelist Robert Heilein also used the phrase in his book "The Moon is a Harsh Mistress." The term means that nothing is free, and if something seems free, it's just that you're getting charged through a back-door means; e.g., a bar might offer you a free lunch but you pay for it in the price of drinks. More likely is that it may be free to for some people, but someone else is picking up the tab. Actually, Robert Heinlein wrote "There ain't no such thing as a free lunch." Often shortened to TANSTAAFL in written conversations these days. "There is no such thing as a free lunch" refers to economics. In economics everything from our time to money is a resource. To have a "free lunch" is to give up a resource, "time", that could be used elsewhere. So although you gain a "free lunch", you lose a resource.