Robinhood is a stock brokerage app that lets you trade individual stocks for $0. Which is nice considering that most sites charge brokerage fees from @$4-14. I've been using Robinhood for a little over a year, and I love it.
Right now they have a promotion going on where if you sign up through an established account you both will get free shares of a company. If you're interested I'll provide the link.
link : http://share.robinhood.com/zachgar223