The phrase “there is no free lunch” is an idiom that means one cannot get something that is desired or valuable without having to pay for it in some way. It is often used to convey the idea that anything one receives for free will be paid for in another way, such as by hidden costs, externalities, or opportunity costs. The phrase originated from the practice of American bars offering a “free lunch” to customers who bought drinks, but the food was usually salty and made them buy more drinks . The acronym TANSTAAFL (There Ain’t No Such Thing As A Free Lunch) is also used to express this concept. The phrase and the acronym are popular in economics literature and have been used by authors such as Robert A. Heinlein and Milton Friedman.
