It’s hard to answer that without actually seeing a modern gift economy in action. Luckily, modern gift economies actually do exist. On a small scale, they exist among friends, who might lend each other a vacuum or a cup of flour. There’s even an example of a gift economy on a much larger scale, albeit one that’s not always in operation: The Rainbow Gathering, an annual festival in which about 10,000 people gather for a month in the woods (it rotates among various national forests around the country each year) and agree not to bring any money. Groups of attendees set up “kitchens,” in which they prepare and serve food for thousands of people every day, all for free. Classical economists might guess that people would take advantage of such a system, but, sure enough, everyone is fed, and the people who don’t cook play music, set up trails, teach classes, gather firewood, and perform in plays, among other things.

Men from the visiting group sit quietly while women of the opposite moiety come over and give them cloth, hit them, and invite them to copulate. They take any liberty they choose with the men, amid amusement and applause, while the singing and dancing continue. Women try to undo the men’s loin coverings or touch their penises, and to drag them from the “ring place” for coitus. The men go with their … partners, with a show of reluctance to copulate in the bushes away from the fires which light up the dancers. They may give the women tobacco or beads. When the women return, they give part of this tobacco to their own husbands.
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).[15]
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.
Men from the visiting group sit quietly while women of the opposite moiety come over and give them cloth, hit them, and invite them to copulate. They take any liberty they choose with the men, amid amusement and applause, while the singing and dancing continue. Women try to undo the men’s loin coverings or touch their penises, and to drag them from the “ring place” for coitus. The men go with their … partners, with a show of reluctance to copulate in the bushes away from the fires which light up the dancers. They may give the women tobacco or beads. When the women return, they give part of this tobacco to their own husbands.
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]
Adam Smith, the father of modern economics, sought to demonstrate that markets (and economies) pre-existed the state, and hence should be free of government regulation. He argued (against conventional wisdom) that money was not the creation of governments. Markets emerged, in his view, out of the division of labour, by which individuals began to specialize in specific crafts and hence had to depend on others for subsistence goods. These goods were first exchanged by barter. Specialization depended on trade, but was hindered by the "double coincidence of wants" which barter requires, i.e., for the exchange to occur, each participant must want what the other has. To complete this hypothetical history, craftsmen would stockpile one particular good, be it salt or metal, that they thought no one would refuse. This is the origin of money according to Smith. Money, as a universally desired medium of exchange, allows each half of the transaction to be separated.[2]
Trade did occur in non-monetary societies, but not among fellow villagers. Instead, it was used almost exclusively with strangers, or even enemies, where it was often accompanied by complex rituals involving trade, dance, feasting, mock fighting, or sex—and sometimes all of them intertwined. Take the indigenous Gunwinggu people of Australia, as observed by the anthropologist Ronald Berndt in the 1940s: 

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.
Communities of Iroquois Native Americans, for instance, stockpiled their goods in longhouses. Female councils then allocated the goods, explains Graeber. Other indigenous communities relied on “gift economies,” which went something like this: If you were a baker who needed meat, you didn’t offer your bagels for the butcher’s steaks. Instead, you got your wife to hint to the butcher’s wife that you two were low on iron, and she’d say something like “Oh really? Have a hamburger, we’ve got plenty!” Down the line, the butcher might want a birthday cake, or help moving to a new apartment, and you’d help him out.
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.[20]

If you've ever swapped one of your toys with a friend in return for one of their toys, you have bartered. Bartering is trading services or goods with another person when there is no money involved. This type of exchange was relied upon by early civilizations. There are even cultures within modern society who still rely on this type of exchange. Bartering has been around for a very long time, however, it's not necessarily something that an economy or society has relied solely on.

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.
In England, about 30 to 40 cooperative societies sent their surplus goods to an "exchange bazaar" for direct barter in London, which later adopted a similar labour note. The British Association for Promoting Cooperative Knowledge established an "equitable labour exchange" in 1830. This was expanded as the National Equitable Labour Exchange in 1832 on Grays Inn Road in London.[18] These efforts became the basis of the British cooperative movement of the 1840s. In 1848, the socialist and first self-designated anarchist Pierre-Joseph Proudhon postulated a system of time chits. In 1875, Karl Marx wrote of "Labor Certificates" (Arbeitszertifikaten) in his Critique of the Gotha Program of a "certificate from society that [the labourer] has furnished such and such an amount of labour", which can be used to draw "from the social stock of means of consumption as much as costs the same amount of labour."[19] 
×