As part of Apple's one billion app countdown for their iTunes App Store, they have also compiled a list of the all-time top 20 apps [App Store] for both Paid and Free apps.
Perhaps most interesting is what the potential market for a very successful paid iPhone app might be. A few numbers have been released for some of the top iPhone apps that gives us an idea of the numbers involved. Here is a collection of the known sales numbers for some of the top 20 paid apps. App titles link directly to App Store.
#2. Koi Pond - The New York Times published just a few days ago reveals that Blimp Pilots' virtual pond app has been downloaded an estimated 900,000 times giving the developers about $623,000 after Apple's cut.
#3. Enigmo - Pangea's puzzle game appeared early in the App Store. Pangea's Brian Greenstone recently revealed in a YouTube video that Enigmo sold 810,000 units between July 2008 and January 2009 (likely the bulk of sales). The price of this app has bounced between $9.99 and $0.99 making it difficult to estimate earnings.
#12. Pocket God - This recent hit is another entertainment app that puts you in control of a small island of inhabitants. Bolt Creative's Dave Castelnuovo revealed in a TouchArcade forum post that their app had sold about 500,000 copies as of late March. An impressive feat since it has only been around since January, earning the developers about $350,000 so far.
#19. iShoot - An artillery game by one-man company Ethan Nicholas who is the latest rags-to-riches App Store story. Nicholas revealed to the New York Times that he had made $800,000 in five months. His app has held mostly at a $2.99 pricepoint, which estimates his total sales at over 380,000 downloads.
Article Link: All-Time Top iPhone App Sales Figures and Estimates