Barter is a contract wherein parties trade goods or commodities for other goods, as opposed to sale or exchange of goods for money. Barter is not applicable to contracts involving land, but solely to contracts relating to goods and services. For example, when a tenant exchanges the performance of various maintenance tasks around a house for free room and board, a barter has taken place.
The Owenite socialists in Britain and the United States in the 1830s were the first to attempt to organize barter exchanges. Owenism developed a "theory of equitable exchange" as a critique of the exploitative wage relationship between capitalist and labourer, by which all profit accrued to the capitalist. To counteract the uneven playing field between employers and employed, they proposed "schemes of labour notes based on labour time, thus institutionalizing Owen's demand that human labour, not money, be made the standard of value." This alternate currency eliminated price variability between markets, as well as the role of merchants who bought low and sold high. The system arose in a period where paper currency was an innovation. Paper currency was an IOU circulated by a bank (a promise to pay, not a payment in itself). Both merchants and an unstable paper currency created difficulties for direct producers.
Remember back in school when kids would swap juice boxes for chips, or cookies for Twinkies? Even children have an innate sense that the comparable value of cookies to Twinkies is in the eye of the beholder. To the kid who gets cookies every day, the elusive cream-filled cake treat is worth more than a few, and he realizes his friend might feel differently.
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.