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).
Barter is a system of exchange by which goods or services are directly exchanged for other goods or services without using a medium of exchange, such as money. It is distinguishable from gift economies in that the reciprocal exchange is immediate and not delayed in time. It is usually bilateral, but may be multilateral (i.e., mediated through barter organizations) and usually exists parallel to monetary systems in most developed countries, though to a very limited extent. Barter usually replaces money as the method of exchange in times of monetary crisis, such as when the currency may be either unstable (e.g., hyperinflation or deflationary spiral) or simply unavailable for conducting commerce.
But, since the advent of money-based systems, bartering is an option that most of us dismiss as soon as we get that first paycheck or allowance. Not so for a guy named Kyle MacDonald. He drew a media frenzy when, in a matter of one year and 14 trades, he bartered his way from a paper clip to a house [source: NPR]. Although he had a lot of help from his local government and some people in show business, his story offers dramatic evidence of today's existing market for bartering. MacDonald is one of many people who have taken advantage of the growing phenomenon of bartering over the Internet. This ancient practice is also alive and well in services that facilitate bartering and companies that swap favors.
Search for bartering partners. After you know what you have to offer and exactly what you need/want in a barter situation, find a bartering partner. If you don't have a specific person or business in mind, try word of mouth. Let your friends, colleagues and social network know about your specific need and what you want in a barter situation. Use Facebook, LinkedIn and Twitter.