Have you ever wondered what a week as the number one free iPhone app in the App Store translates to in downloads and ad revenue?

I certainly have and this story gives valuable insight into what it really looks like to be number one in the App Store.

Air Horn, which simply makes a very loud horn noise, was at the top spot for 8 days. During that time, Air Horn has made $20,000 from ad banner advertising and in-app purchases.

Three days before the app hit the top spot, Air Horn had just 5,453 downloads a day, and was ranked 804 on the list.

On the app’s first day at number one, downloads grew to 173,002 that day. A week later, the app was still number one with 129,286 daily downloads.

As the downloads rose, daily ad impressions increased from 160,000 per day to more than two million per day at its peak.

A week after reaching number one, Air Horn had served a total of 4 million 3rd party ad network impressions. The average initial eCPM was $2.06 and increased to an average of $2.62 over eight days.

Are you convinced you can make money with free iPhone apps?

Full story at Techcrunch »