Every society depends on the marketing process to enable the exchange of goods and services between individuals and groups of people. This is also true in a socialist system, even in a primitive tribal hunter-gatherer system, but it may be handled quite a bit differently. There are many ways of handling it. You can just let the chips fall where they may by having no rule at all about what people do...or you can regulate things to one extent or another through laws, licences, etc. The larger and more complex a society gets, the more regulations usually come with it...and it gets harder and harder for ordinary people to understand it and cope with it effectively.