As Orlove noted, barter may occur in commercial economies, usually during periods of monetary crisis. During such a crisis, currency may be in short supply, or highly devalued through hyperinflation. In such cases, money ceases to be the universal medium of exchange or standard of value. Money may be in such short supply that it becomes an item of barter itself rather than the means of exchange. Barter may also occur when people cannot afford to keep money (as when hyperinflation quickly devalues it).[14]
Economic historian Karl Polanyi has argued that where barter is widespread, and cash supplies limited, barter is aided by the use of credit, brokerage, and money as a unit of account (i.e. used to price items). All of these strategies are found in ancient economies including Ptolemaic Egypt. They are also the basis for more recent barter exchange systems.[17]
The man who arguably founded modern economic theory, the 18th-century Scottish philosopher Adam Smith, popularized the idea that barter was a precursor to money. In The Wealth of Nations, he describes an imaginary scenario in which a baker living before the invention of money wanted a butcher’s meat but had nothing the butcher wanted.“No exchange can, in this case, be made between them,” Smith wrote.
While Swapsity trades are facilitated online, its participants can be seen in real life at themed in-person swap meets as well as the annual Live Green Toronto Festival. Over the past three years, more than 25,000 items—primarily clothes, books, CDs and DVDs—have been swapped at its events, collectively saving people roughly $200,000. About 5,000 items have been donated to charity. On average, each participant saves $80 at every swap (the value of items they go home with and would have otherwise bought). This year’s Live Green event was packed despite the grey July weather: until it started to rain heavily in the late afternoon, lineups to get into the six swapping tents spanned the full length of the waiting area, then folded in on themselves like accordions. Even in the rain, the leaking tents bustled.