As I’m interested in creating my own iPhone app, I’ve researching which type of app sells and which app of each genre is a good seller.
Sales figures do not appear in the iTunes App store but the number of reviews do. There’s a method to questimate the number of sales from the number of reviews. See Guess sales figures. This method suggests a review to sales ratio of 350:1, that is 1 review would equal 350 sales.
The responses to Peter Melnikov’s post seem to agree to the ratio with some reservations and exceptions, so until a better method is found I’ll use his!