Freemium applications are driving in-app purchases according to a new report from Distimo, which was completed for the Verizon Developer Community. It is like getting a free ice cream sample at Baskin-Robbins: give a consumer a taste of something for free and then let them come back for more. Just 4% of all iPhone applications feature in-app purchases but, among the 200 highest-grossing applications in the iTunes App Store, 72% of the application revenue came from those with in-app purchases. That figure is up from just 28% last year. The revenue landscape is similar in the Android Market. 68% of the 25 top-grossing apps in the Android Market offer in-app purchases. Distimo also found that the average application in the iTunes App Store costs $3.84 while the average Android application costs $3.30.