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.
Bartering does have its limitations. Many bigger (i.e., chain) businesses will not entertain the idea and even smaller organizations may limit the amount of goods or services for which they will barter (i.e., they may not agree to a 100% barter arrangement and instead require that you make at least partial payment). But in an economic crunch, bartering can be a great way to get the goods and services you need without having to pull money out of your pocket.
But the harm may go deeper than a mistaken view of human psychology. According to Graeber, once one assigns specific values to objects, as one does in a money-based economy, it becomes all too easy to assign value to people, perhaps not creating but at least enabling institutions such as slavery (in which people can be bought) and imperialism (which is made possible by a system that can feed and pay soldiers fighting far from their homes).
An alternate currency, denominated in labour time, would prevent profit taking by middlemen; all goods exchanged would be priced only in terms of the amount of labour that went into them as expressed in the maxim 'Cost the limit of price'. It became the basis of exchanges in London, and in America, where the idea was implemented at the New Harmony communal settlement by Josiah Warren in 1826, and in his Cincinnati 'Time store' in 1827. Warren ideas were adopted by other Owenites and currency reformers, even though the labour exchanges were relatively short lived.
In trade, barter (derived from baretor) is a system of exchange where participants in a transaction directly exchange goods or services for other goods or services without using a medium of exchange, such as money. Economists distinguish barter from gift economies in many ways; barter, for example, features immediate reciprocal exchange, not delayed in time. Barter usually takes place on a bilateral basis, but may be multilateral (i.e., mediated through a trade exchange). In most developed countries, barter usually only exists parallel to monetary systems to a very limited extent. Market actors use barter as a replacement for money as the method of exchange in times of monetary crisis, such as when currency becomes unstable (e.g., hyperinflation or a deflationary spiral) or simply unavailable for conducting commerce.