“Eighteen months ago, when I left Ubisoft to start an independent game studio and focus on making my own games, I looked online a bit to get an idea of how much income I could expect to make as an indie. At Ubisoft I used to work on big AAA console games, and I had some figures in mind, but I knew they wouldn’t be relevant for my new life: $20M budgets, teams of 200 hundred people, 3 million sales at $70 per unit… I knew being an indie developer would be completely different, but I had very little information about how different it would be.”
This article from January 2012 provides some really good insight into how much money you can expect to make on a game if you get lucky on the App Store. Well worth a read in case you (like me) missed it.
Read: Money and the App Store: A few figures that might help an indie developer (thegamebakers.com)