5th
This is the best deal I have seen with my online broker
First of all I get two free trades out of this if you join. Second this is a great way for you to get $50 worth of Groupon or whatever other stock you want for free.
The reason I like Sharebuilder is because there is no monthly fee, no limit to how many shares you buy (you can buy $5 worth of stock and smile), and it is easy to use.
Get $50 when you start investing. ShareBuilder actually makes #investing easy: https://www.sharebuilderfriends.com/startnow