Interesting TechCrunch item that deals with the question of…
According to AdWhirl free iPhone apps can serve several advertisements (3 to 5) while a person uses an app. They estimate that apps in Apple’s top 100 free apps list can make between $400 and $5000 per day. That’s a pretty healthy amount of cash per month.
However, do take into account the following factors:
– There are a lot of free iPhone apps (many thousands) competing to get into those top 100 positions
– Apps rise and fall off the chart. So, don’t expect to generate that kind of income from a single app over a long period of time (although it is possible).