When and why does the exchange of goods occur among the most ancient people?

Commodity exchange arose among the most ancient people with the appearance of a surplus and a need for objects that they themselves were not able to produce. The fact is that the universal equivalent of value has not yet existed, and people need various objects regardless of time. At first they got the right things by the tough way of robbery, but soon people invented a mechanism for exchanging goods. For example, if a buckwheat farmer wants to get his hands on oil, he exchanges his product either directly or through exchange for the item that the owner of the oil requires.