People who are searching or browsing the store for cool new apps generally look at things in this order:
1. The name of the app. Does it sound interesting or like it does what they are looking for?
2. The icon. You need to have an attractive icon. If your icon sucks, your app probably does too. Or at least that’s what people think and then they’re gone.
3. The screenshots. You need to have good screenshots that are exciting and that make it clear what your app is about. A lot of developers go further than just regular screenshots; they turn these images into small billboards for their app.
4. If you didn’t lose the potential customer in the previous three steps, they might finally read your description for more info.
5. The price. If you’ve convinced the customer they really can’t live without your app, then the price usually doesn’t matter that much anymore.
So get your visuals to do most of the selling for you. Even if you can’t afford to hire a good graphic designer to do your app’s user interface, at least invest in a good icon. It will make a world of difference in sales.