A typical iPhone contains $80 worth of apps; only 7% have only free apps

"Average number of apps per device - 65
Average spent per iPhone - $80
Average price of a paid app installed - $1.56
Media price of a paid app - $0.99
% of users who only have free apps - 7%
Extrapolated value of the total apps market - $3.3bn"
Source: AppsFire presentation, 6th September 2009