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).
Some entrepreneurs are already taking the principles of swapping—use everything and anything you already have to survive—to create another offshoot system, one that turns a hefty profit. Called the sharing economy, it is perhaps best exemplified by Airbnb, a service that enables people to rent out their apartments like hotels. Other sites let you turn your driveway into a parking space, your car into a taxi and your tools into a rental service. Forbes estimates revenue flowing through the U.S. sharing economy will hit $3.5 billion by the end of 2013, and maybe more. It’s worth mentioning that some business associations and government members are terrified of this rise: like most alternative economies, it’s largely tax-free.
Since the 1830s, direct barter in western market economies has been aided by exchanges which frequently utilize alternative currencies based on the labor theory of value, and designed to prevent profit taking by intermediators. Examples include the Owenite socialists, the Cincinnati Time store, and more recently Ithaca HOURS (Time banking) and the LETS system.