There's a book called "The Social Construction of Reality." Some of it is a little difficult to grasp as it gets into a lot of social science elements, but the basic gist is that everything in our societies are abstractions we have to believe in collectively.
School systems, justice departments, police departments, et. al. don't really exist. They exist because we believe they do. Enough people believe money system works that we can trade money in exchange for labor, potentially adding value to something and building capitol. You can chose to believe such things don't exist and murder 10 people, but enough people believe those structures exist that you'd quickly be put in a prison, or at least a mental institution.
Money and markets are one of the most interesting abstractions of our time. I highly recommend Debt The First 5,000 Years, in which Graeber argues that the earliest forms of money in human history were credit based (not barter like you learn in high school). Wealth was always an abstract belief, and hard money (like coins) came about directly through war (conquerors had to tax areas they took, paid their soliders with coins and where thereby supported by the regions they held as the people were forced to give goods to solders in order to pay taxes) and markets cannot exist without states.