I'm wondering why you've chosen such a competitive category. You're in the same league as Runkeeper, Nike, Fitbit, and all the other fitness trackers and they make their income through the sale of devices so they can afford to put their app up for free.
How about picking a niche that doesn't have their need satisfied yet and charging money directly for that? Maybe designing a grader for teachers, or a tool for gov workers to submit reports, or a business expense tracker. There are lots of categories looking for a design overhaul and with just a little bit of research and effort you can make your app stand out from the pack of existing shitty solutions.