I got Zynga, my girlfriend got Groupon. It takes a couple days and you have to hold on to the stocks for a couple days (I don't think Zynga has much of a future lol) but it's basically a free spin on a guaranteed slot machine. Robinhood is a free stock trading app.
You have to use a referral code to sign up and get free stock, here's mine:
http://share.robinhood.com/andonz