Money is one of the important concepts, This section talks about money from the perspective of microeconomics.when people exchange goods and services without using money, this is called barter. "I'll cook dinner if you'll do the dishes" is an example of barter. Imagine an economy in wich i can sell services as a consultant to banks, but what i want is to buy a new suit. the clothing store that sell suits does not have any use for my services as a banking consultant. i sell consulting services for money, and i buy a suit using money. money serves as a medium of exchange. the bank does not sell suits. how can barter work?
Maybe you go to a store where they are selling suits and offer to do some work for them like cleaning and you know whatever work that is worth the suit you need, lol. Well, if the world was still into trade by barter there will be ways for you to do that and get what you need, you will always have something to exchange with. During the time of trade by barter, I believe there are such things as precious stones, so you can always exchange with them.