Michael Linton originated the term "local exchange trading system" (LETS) in 1983 and for a time ran the Comox Valley LETSystems in Courtenay, British Columbia.[26] LETS networks use interest-free local credit so direct swaps do not need to be made. For instance, a member may earn credit by doing childcare for one person and spend it later on carpentry with another person in the same network. In LETS, unlike other local currencies, no scrip is issued, but rather transactions are recorded in a central location open to all members. As credit is issued by the network members, for the benefit of the members themselves, LETS are considered mutual credit systems.

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]

Simmons learned how to ask after one Barter Babe, a veteran barterer, told her she needed to post a wish list. Following the advice, she eventually got not just one bike but two (one for her and one for Matt), a TTC pass, yoga lessons, a haircut and food she wanted to eat, among hundreds of other things. Simmons made exceptions for some unique trades, too, such as both circus performance training and butter churning lessons, the latter of which she now barters as a skill to others. She even worked up the nerve to approach local businesses in person, armed with a business case for barter. One café near her apartment traded a month’s worth of morning coffee for a financial session; a boutique hotel, Hotel Ocho at Queen and Spadina, took a financial seminar luncheon for its employees in return for an overnight stay for Simmons’s parents, who were celebrating their 35th anniversary.
Barter Network Ltd. is a proud member of The International Reciprocal Trade Association, IRTA, which is a non-profit organization committed to promoting just and equitable standards of practice and operation within the Modern Trade and Barter and other Alternative Capital Systems Industry, by raising the awareness and value of these processes to the entire Global Community. IRTA provide all Industry Members with an ethnically based global organization, dedicated to the advancement of Modern Trade and Barter and other Alternative Capital Systems, through the use of education, self-regulation, high standards and government relations. The Board of IRTA consists of Key Players in the Barter Industry, With Patti Falus President of Barter Network Ltd. being the only Canadian who sits on the Board.
While there are most certainly safety considerations – and in some cases, a time commitment – bartering can be quite rewarding. You may not have a surplus of spendable money, but you do have talents, skills, and miscellaneous goods that are just as good as cash. With a little thought, and willingness to make the effort, you can use bartering to obtain the goods and services you want without impeding your cash flow.
Other countries, though, do not have the reporting requirement that the U.S. does concerning proceeds from barter transactions, but taxation is handled the same way as a cash transaction. If one barters for a profit, one pays the appropriate tax; if one generates a loss in the transaction, they have a loss. Bartering for business is also taxed accordingly as business income or business expense. Many barter exchanges require that one register as a business.
David Graeber argues that the inefficiency of barter in archaic society has been used by economists since Adam Smith to explain the emergence of money, the economy, and hence the discipline of economics itself.[2] "Economists of the contemporary orthodoxy... propose an evolutionary development of economies which places barter, as a 'natural' human characteristic, at the most primitive stage, to be superseded by monetary exchange as soon as people become aware of the latter's greater efficiency."[3] However, extensive investigation by anthropologists like Graeber has since then established that "No example of a barter economy, pure and simple, has ever been described, let alone the emergence from it of money; all available ethnography suggests that there never has been such a thing. But there are economies today which are nevertheless dominated by barter."[4]
While it may be free, there is no one monitoring the barter ads, so you must be aware of potential Craigslist scams, and realize that you are always at risk when it comes to meetups and exchanges. For example, about a year ago, I arranged to trade massage gift certificates for housecleaning. Since the individual was coming to my home, I was more nervous than usual. However, she offered good previous references, and we  arranged for a time to meet when my husband would be home, in case an odd, unexpected, or even dangerous situation arose.
Check online swap markets and online auctions that have a bartering component such as Craigslist.com (check under "For Sale" for the Bartering category), Swapace.com, SwapThing.com, Barterquest.com, U-Exchange.com, Trashbank.com and Ourswaps.com. Check for local bartering clubs. Your local Chamber of Commerce may be able to provide you with information on similar clubs in your area.