Free lunch was a tradition once common in saloons in the US. It was a sales enticement that offered a meal at no cost to attract customers and build patronage. So popular was the scheme that a complete meal was offered with a 15 cents drink and people used to throng to such saloons, a few of them even complaining about the quality of food. On the other hand, it was Milton Friedman who popularized the term ‘No free lunch’ with his book. The term meant that in reality, a person or a society cannot get “something for nothing”. In mathematical finance, this was an informal synonym for the no-arbitrage principle.