The common idea of a market is a place where commodities are bought and sold. Now the idea of a market does not rely on any physical location. All that is needed is a demand for a commodity and a way to meet that demand. Money is just a commodity like any other thing, as strange as it sounds. In fact, the market for money is the largest market in the world. forex markets worldwide trade over a trillion dollars each and every single day. They are very different from other kinds of markets because of the nature of currencies and the vagaries of the concept of value.