Some time ago I came across David Graeber’s Debt: The First 5,000 Years. I only skimmed it (I should read it sometime). The main takeaway for me was that money is debt. Not wealth, or value, but debt. Money is something that represents that the rest of humanity owes you something. Individuals might not owe you anything, but, if money is still worth anything, some individuals will respond to that debt.
The interesting thing about money is that is a sort of platformized debt. It’s not a debt that someone in particularly owes you. With money, you can either accept offers from others, or make your own offers to others. The essence of a market, then, is as a place to either acquire or consume debt. If our needs are satisfied by the work of others, and our work satisfies the needs of others, a market is where we buy and sell debt. Production (including delivery) would then be buying debt, and consumption would then be selling debt.
Not every transaction is (or should be) possible: we have legal systems in place exactly for that reason. But it also makes sense that, within the limits of proper regulation, there is freedom to make these exchanges of debt.