App Store pricing is often referred to as a race to the bottom, but that doesn't mean that every app has to be free. Some developers, usually the ones with quality apps, dare to charge a fair price for their wares, and that's the way it should be. That being said, there's no better way to get some attention for your paid-for app than to make it free for a limited time. Free downloads count towards an app's App Store chart ranking even when it moves back into the 'Paid' chart, which should in turn mean more sales. It's genius really, when you think about it.
