http://en.wikipedia.org/wiki/TANSTAAFLTANSTAAFL is an acronym for the adage "There Ain't No Such Thing As A Free Lunch," popularized by science fiction writer Robert A. Heinlein in his 1966 novel The Moon Is a Harsh Mistress, which discusses the problems caused by not considering the eventual outcome of an unbalanced economy. This phrase and book are popular with libertarians and economics textbooks. In order to avoid a double negative, the acronym "TINSTAAFL" is sometimes used instead, meaning "There Is No Such Thing As A Free Lunch".
In 1950, a New York Times columnist ascribed the phrase to economist (and Army General) Leonard P. Ayres of the Cleveland Trust Company. "It seems that shortly before the General's death
... a group of reporters approached the general with the request that perhaps he might give them one of several immutable economic truisms which he had gathered from his long years of economic study... 'It is an immutable economic fact,' said the general, 'that there is no such thing as a free lunch.'"<2>
"Oh, 'tanstaafl'. Means 'There ain't no such thing as a free lunch.' And isn't," I added, pointing to a FREE LUNCH sign across room, "or these drinks would cost half as much. Was reminding her that anything free costs twice as much in the long run or turns out worthless."
Manuel in The Moon Is a Harsh Mistress (1966), chapter 11, p. 162, by Robert A. Heinlein<3>
"There's no such thing as a free lunch."
popularized by economist Milton Friedman<4>;