We're thinking of an up-sell strategy. Our team has a lot of financial experience (ex-wall street), and there are many advanced products such as portfolio analytics, diversification metrics and risk ratios etc. that we could sell.

A basic stocks app is our way of reaching our target audience.

To be honest though, this is more a guess that anything else. Hopefully we won't have to do banner ads without the app. Those are really ugly.

The question is how is it free? They must be pulling the data from some free source else these real time stock quotes cost a lot.

Yes, we are. We might have to move to a proper paid service like BATS when this gets bigger.

http://www.quora.com/Stocks-financial/Where-do-sites-such-as...