While it's easy to assume (and you know what happens when you assume) that being one of the top downloads in Apple's App Store would mean you and your company are rolling in the money, a new survey shows that not to be the case.     

According to AppInTop and CPIEra.comwho posted a blog to the Huffington Post, many of your favorite free app in iTunes isn’t making much money, if any at all. The only apps making significant money, according to the blog post, are those who are offering in-app purchases. Of the top 50 free apps in the App Store, AppInTop says only 12 make money on a daily basis.     

When its blog was posted, the top 10 apps included Piano Tiles, Battery Doctor- 2048, Notability, Snapchat, Don't tap the White Tile 2, Dots, Make It Rain: The Love of Money and Facebook Messenger. Of those only Dots and Make It Rain are generating money. The biggest earners after the top 10 are Swamp Attack, 8 Ball Pool, Beats Music, Pandora Radio, Clash of Clans, Dwarven Den, SoundCloud, Frozen Free Fall, Skype for iPhone and Perfect 365.  

 "Interestingly, only Dots and Make It Rain are making money," writes Natasha Starkell, with Mobile marketing analytics for CPIEra.com. "For Dots the revenue is nearly $1,800 on that day that extrapolates to $656,000 per year (assuming that the app stays in the rating throughout the year). For Make It Rain in-app monetization appears to work better. The app makes $7104 per day and the equivalent of nearly $2.6 million per year."    

"Amongst the top 50 overall free apps in the Apple App Store the biggest earners are Clash of Clans ($168'000 revenue per day, 33,700 downloads per day) and Pandora ($120'000 revenue per day, 34'900 downloads per day)," Starkell continues.     

One big flaw of AppInTop's ranking is that the revenue it posts for each app does not include advertising. Advertising in mobile games can be big money, just ask Flappy Bird developer Dong Nguyen. Prior to its removal from the App Store, Nguyen said the game was generating $50,000 a day in advertising.     

To read the rest of AppInTop's blog post, click here.