When two people each have items the other wants, both people can determine the values of the items and provide the amount that results in an optimal allocation of resources. Therefore, if an individual has 20 pounds of rice that he values at $10, he can exchange it with another individual who needs rice and who has something that the individual wants that's valued at $10. A person can also exchange an item for something that the individual does not need because there is a ready market to dispose of that item.
Inevitably some people may feel like they were taken advantage of. One way to diminish inequities is to engage in dollar-for-dollar trades. For example, if you would like to trade your housecleaning service for someone’s couch, try to break down the goods and services to the dollar amount. If the two of you decide that the value of the couch is worth $200, why don’t you supply a gift certificate for $200 worth of housecleaning services? It’s a wise course and ensures all parties know what they are getting and what they are offering.
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.
During economic downturns, when there is a keenly felt shortage of jobs and cash, people have historically adopted barter systems. The world’s most established bartering-style system is Switzerland’s wir: the German word for “we” as well as the abbreviation of Wirtschaftsring, which translates loosely to “economic circle.” In 1934, the economy in Switzerland had tanked—as it had in much of the world. Two businessmen who were facing bankruptcy, Paul Enz and Werner Zimmermann, gathered 15 of their associates in Zurich and hashed out a solution: a mutual credit system.