I wanted to see what people thought the purpose of money is.
I asked a friend and she said: "Money is for rich people"
So what do you think money is for? What would you do without money?
Money serves as a medium of exchange, because trying to divide a goat to purchase a chicken, which is obviously worth less than a whole goat would have been inefficient. Who wants to carry around a carcass.
Money varies in its physical aspects, it has been anything from large round stones, to clam shells. However, it has, up until the creation of the Federal Reserve, been a commodity. Something that has value outside of itself that is recognized by everyone.
Gold, Silver, and Copper are traditional currencies. Gold is suitably rare, while Silver is not as rare, and copper is relatively common, thus the typical old style tiered system where Gold is more valuable than silver is more valuable than copper. However, there was common agreement by just about everyone that those three metals had some value and that is what made them a commodity.
They were then used as measures of the value of other products. So much Gold, Silver or Copper to purchase something, be it a chicken, cow, or goat, or so much of something to purchase a unit of Gold, Silver or Copper. In the United States that unit of Gold was called a dollar and was set at 1/20th of an oz. of Gold.
It was not until the creation of the Federal Reserve, and an imbecile named FDR that the United States separated its money from Gold, a move that has lead to a great amount of suffering, poverty and misery in this nation.
Though I suppose I should stop offering the text book answers and give you my personal answer.
It offers liquidity in assets so that assets can easily be transformed from one type to another. For instance, labor into food, gas, shelter, water, heating, air-conditioning, etc.