For instance, each time Apple releases a new version of the iPhone, the second-hand market for older versions of the iPhone enjoys a flurry of activity. However, you do have to be as careful with the barter of used goods as you would be with the purchase of used goods. Be sure everything is in working order and shows no signs of significant damage.
Economic historian Karl Polanyi has argued that where barter is widespread, and cash supplies limited, barter is aided by the use of credit, brokerage, and money as a unit of account (i.e. used to price items). All of these strategies are found in ancient economies including Ptolemaic Egypt. They are also the basis for more recent barter exchange systems.[17]
The whole point of barter is to satisfy a need. A valuable barter is whatever a barterer needs at that moment. Raj Dhiman, a 30-year-old chemist, joined Swapsity at the beginning of 2012. For his first barter, he traded a batch of home-baked gluten-free muffins in return for a full weekend first aid course. Unlike the course’s instructor, Dhiman relished the challenge of perfecting the recipe. Since then, he’s exchanged a lesson on how to create a website for an Indian cooking class. He’s also turned away barter offers that he didn’t find personal value in. “It’s perfectly fine to decline,” he says, “It wasn’t like, ‘Whoa, whoa, whoa. What is this person thinking?’ I’d say, ‘I appreciate the offer, but that’s not what I need right now.’ All you have to do is ask for what you need.”
“Economic theory has always got to be historically bounded,” Beggs says. “I think it’s a mistake to think you’ll find the workings of modern money by going back to the origins of money.” He does point out that, while barter may not have been widespread, it’s possible that it happened somewhere and led to money, just given how much is unknown about such a large period of time. 

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.
On paper, this sounds a bit like delayed barter, but it bears some significant differences. For one thing, it’s much more efficient than Smith’s idea of a barter system, since it doesn’t depend on each person simultaneously having what the other wants. It’s also not tit for tat: No one ever assigns a specific value to the meat or cake or house-building labor, meaning debts can’t be transferred.