Foreign exchange trading is the trading of currencies. Most currencies can be traded. Huge amounts of currencies are traded 24 hours a day, 5 days a week. On average $1.9 trillion is traded a day. The most traded are United States Dollar, Japanese Yen, Euro, Canadian Dollar, British Pound Sterling, Australian Dollar and Swiss Franc.
Many brokers will let you open an account with a starting balance of just $250. Though that may seem small, remember you will be trading on margin. Your $250 investment may let you control $25,000. As with all investments there are risks so make sure you take the time to study the markets and your exposure before making your first trades. I highly recommend that you do some paper trades first to make sure you have understood how the markets work. No risk training, just write down the trades you would have done for real and chart the prices. Buy and sell and see if you have the right strategy before making real trades.