You can start trading immediately on sites like Sharebuilder (given that you're of legal age, if not, get a parent to help). Assuming you know nothing now, you

You can start trading immediately on sites like Sharebuilder (given that you're of legal age, if not, get a parent to help). Assuming you know nothing now, you can easily start reading up on sites like investopedia.com (http://www.investopedia.com/university/buildingblocks.asp http://www.investopedia.com/university/buildingblocks.asp). You can also open "play" money accounts on stock market simulations. Have fun.