App store analytics company Distimo says that the average price of applications is on the decline amid the growth free applications, according to its latest trends report.

The average price of apps dropped as the growth of free apps outpaced the growth of paid apps at the Apple App Store, BlackBerry App World, Google Android Market and Nokia Ovi Store. Distimo says the top 300 free apps in the United States generated an average of more than 3 million downloads every day in December 2010, with only 350,000 paid applications downloaded daily during that month.

Prices fell the most at the Nokia Ovi Store, with the average app’s selling price across the whole store falling 29 percent and the price of the store’s top 100 applications falling 61 percent.

Apple posted storewide price declines of 12 percent while the price of its top 100 apps dropped 19 percent. The price of BlackBerry’s storewide apps and top100 apps both declined 24 percent. The only app store in Distimo’s report to have any rise in prices was Google’s Android Market, which posted a 1 percent rise in prices across the entire store even as the price of its top 100 apps slipped 9 percent.

Distimo reports that the trend toward free apps is pushing developers to find other ways of making money off their applications. Sales from in-app purchases have steadily increased over the past year, and revenue from in-app purchases on the iPhone and iPad more than doubled over the second half of last year.

The company also reported that Apple’s app store grew the most in 2010 in terms of the absolute number of applications, doubling to nearly 300,000 apps. Google’s Android Market now has nearly 130,000 apps, six times the amount it had last year. BlackBerry App World and Nokia Ovi Store swelled to nearly 18,000 applications and 25,000, respectively.