Well, now we come back to the history of economics.
Buying something is nothing else than exchanging for something everyone (more or less) wants to exchange (=money. Everyone wants it, because everyone knows he can exchange anything for it, with everybody).
If you want to have a heirloomed bow, but the owner of a bow wants a sword, not your axe, you would need to find someone with a sword, willing to exchange for an axe to get your bow. If you find someone with a sword, but he wants a crossbow, you need someone with a crossbow willing to exchange for an axe, and so on.
With money you wouldn't need to "organize" exchanges, everyone could always exchange his heirloom for money first, and then exchange the money for the heirloom he wants to have. That's the point of money, the increased flexibility of exchanging.
In other words: I think you are wrong.