Instead of having money why don't we all just give each other stuff for free? You know, like if you need a couple of tomatoes I would give you them and you could give me a medium sized turnip in exchange. That sort of thing.
Actually I need my tomatoes for tomorrows sandwiches but I have got half a cucumber if that's acceptable? And I prefer swede to turnip please.
It's not a perfect system yet. There are a few things to iron out.