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. 

In trade, barter (derived from baretor[1]) 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.[2] 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.
Debts in the wir currency, assigned the same value as the Swiss franc, could be paid with sales to any member of the bartering circle: if a baker needed to “purchase” eggs and flour from a farmer, the baker could pay off the debt by “selling” baked goods to another wir member. The farmer, in turn, could use his newly acquired credit to “buy” his own needed items or services. Despite a bank-led campaign to discredit the system, wir stuck. Today, it has more than 60,000 business participants and does the equivalent of about $4.4 billion in annual trade.
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.
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]
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.
Anthropologists have argued, in contrast, "that when something resembling barter does occur in stateless societies it is almost always between strangers, people who would otherwise be enemies."[6] Barter occurred between strangers, not fellow villagers, and hence cannot be used to naturalisticly explain the origin of money without the state. Since most people engaged in trade knew each other, exchange was fostered through the extension of credit.[4][7] Marcel Mauss, author of 'The Gift', argued that the first economic contracts were to not act in one's economic self-interest, and that before money, exchange was fostered through the processes of reciprocity and redistribution, not barter.[8] Everyday exchange relations in such societies are characterized by generalized reciprocity, or a non-calculative familial "communism" where each takes according to their needs, and gives as they have.[9]
No, said Mises, for if taken back far enough, there comes a point at which money first emerges as a medium of exchange out of a pure barter economy Prior to this, it is valued only for its non-monetary uses as a commodity The demand for money is therefore pushed back to the last day of barter, where goods are traded only in direct exchange, and where the temporal element of the regression theorem ends It is in this way that all charges of circularity are obviated.
Yet after three years with the firm, she was dissatisfied. She was spending all her time advising millionaires when she wanted to work with average Torontonians, especially women. She couldn’t help noticing that most of her female friends were broke, confused and floundering. Online, her social media feeds were filled with panicky talk of recession budgets and empty wallets. There was one problem: those women couldn’t afford to pay her, and she certainly couldn’t afford to work for free. “I really wanted to do it,” she says, “but I couldn’t figure out a business model.”
When exchanging services, it’s important to remember that bartering is considered income. While you may be able to write off expenses you incur during the barter, you must claim the fair market value of the services you provided as income. For example, if you charge $60 an hour as a massage therapist, and you trade a one-hour massage for housecleaning services, you may have to claim the equivalent income. When you trade assets, you may even be responsible for tracking capital gains or losses. If you have any doubts or questions, consult the IRS website.