The existence of money isn't the problem. Unless you want to grow your own food, make your own clothes, and do your own surgery, sooner or later you're going to

The existence of money isn't the problem. Unless you want to grow your own food, make your own clothes, and do your own surgery, sooner or later you're going to want something from someone else that you need to trade for, and money is a better way of dealing with that than having to hunt down someone who has what you want and will take some of your chickens or whatever in exchange.