Research from Distimo points to a correlation between increasing screen size and increasing the amount consumers are willing to pay for an application.
The average selling price of the top 300 applications for Mac OS devices (e.g. iMacs and Macbooks) is USD 11.21. It falls to USD 4.19 for iPad and USD 1.57 for iPhone (source: Distimo).
It seems the small the screen, the less users are willing to pay.
Of course, there is an argument the additional power of Mac OS devices means the applications deliver a greater functional benefit and therefore justify a higher price. Similarly, most Mac OS applications have a legacy pricing model which pre-dates the iOS app store, when prices for software were generally higher.
However, the variation between prices for iPad and iPhone is noteworthy. Although the physical size of the screens is quite different, the number of pixels is similar: 1024 x 768 on the iPad versus 960 x 640 on iPhone 4.
It seems consumers are getting more pixels for their money on iPhone than on iPad.
These pricing variations raise an interesting question about pricing models for multi-screen experiences, where an application is either replicated across each of the platforms, or relies on each device to deliver different parts of the overall experience. How will developers price for these kind of services?