Unlike stock markets, which can trace their roots back centuries, the forex market as we understand it today is a truly new market. Of course, in its most basic sense - that of people converting one currency to another for financial advantage - forex has been around since nations began minting currencies. But the modern forex markets are a modern invention. After the accord at Bretton Woods in 1971, more major currencies were allowed to float freely against one another. The values of individual currencies vary, which has given rise to the need for foreign exchange services and trading.
In the forex market currencies trade in lots, called micro, mini, and standard lots. A micro lot is 1000 worth of a given currency, a mini lot is 10,000, and a standard lot is 100,000. This is different than when you go to a bank and want $450 exchanged for your trip. When trading in the electronic forex market, trades take place in set blocks of currency, but you can trade as many blocks as you like. For example, you can trade seven micro lots (7,000) or three mini lots (30,000) or 75 standard lots (750,000), for example.