Stocks app have been around since the beginning of iOS, Apple even includes one by default. However barely any of these apps are actually that useful, they're also pretty ugly and hard to get around.
StockTouch by far is the best stocks app I've come across so far. The first thing you notice when you launch the app is the design, especially the bright colours. The colours aren't there to just look fancy though, the colours represent either an increase or decline in the value of stocks. Red means decline and green means increase. Black means not much change. The colours get harsher depending on the percentage increase/decline.
When you first launch the app you're given the nine main industries. You can then tap through to each one to find out the leaders in each one.
There's a nice little slider on the right which lets you choose time. You can have a look at stock changes over a day, a week, a month, 3 months, 6 months, a year or 5 years.
If you can't find the stock you're looking for you can simply search for it.
Tapping through to a stock shows the name, percentage change, position in the industry, a graph showing changes, description of the company, news about the company and some other vital information.
The app is perfect for anyone who monitors stocks and it could easily be used to track stocks you may be interested in buying.