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.
Trade is the negotiation and exchange of goods and services for money or for desired goods and services that are possessed by another. Trade, on the other hand, is a broader term which includes barter system, purchase of goods using money, international trade between countries, commodities trading, currency trading, stocks and bonds trading, etc. When the world developed, the concept of currency and money as a medium of exchange trade between parties became a simple exercise as a fixed and fair price was determined for each product or service. Nowadays trade is conducted in many platforms including international trade which is the trade of goods and services among countries through the payment of international currencies such as the USD, GBP, JPY, etc. However, this involves exchange rate risk which can be quite costly. Trading also occurs on share markets wh ere investors buy and sell securities. Commodities traders and currency traders also trade commodities and currencies with the aim of making profits.
For instance, let's say your pipes burst at your home and you find yourself in need of a plumber. It's an emergency situation and if you don't hire a plumber fast, you'll be displaced and will have to move your family out of the house and into a temporary living situation. That certainly would be a bad thing. But should you barter your dog grooming services right now? Do you really want to trust your plumbing to the only person in town who'll do the job if you shampoo their poodle?
Other anthropologists have questioned whether barter is typically between "total" strangers, a form of barter known as "silent trade". Silent trade, also called silent barter, dumb barter ("dumb" here used in its old meaning of "mute"), or depot trade, is a method by which traders who cannot speak each other's language can trade without talking. However, Benjamin Orlove has shown that while barter occurs through "silent trade" (between strangers), it also occurs in commercial markets as well. "Because barter is a difficult way of conducting trade, it will occur only where there are strong institutional constraints on the use of money or where the barter symbolically denotes a special social relationship and is used in well-defined conditions. To sum up, multipurpose money in markets is like lubrication for machines - necessary for the most efficient function, but not necessary for the existence of the market itself."