Selling has been around for ever. In fact it started around 6000 BC when people traded all sorts of goods and services, such as weaponry, food, or tea. The problem before money came around was that there was no way to assign a value to the goods and services that were being traded. Is a goat worth two pairs of shoes? Is salt a more valuable commodity than butter? Clearly, even in today’s commercial world, the value of something is related to what someone is prepared to pay and what you’re prepared to accept. That’s true whether you’re buying a car or selling your time as a service. The early traders had to establish a system of value or worth where they could get what they wanted from the deal.