Free apps displaying in-app advertising do suck the life out of your cellphone’s battery. A team led by Abhinav Pathak, a computer boffin at Purdue University, Indiana, found that around “65%-75% of energy in free apps is spent in third-party advertising modules.”
This means that free apps like Angry Birds and Facebook may actually cost you more than paid apps in the long run.
The researchers studied (PDF) Android and “Windows Mobile”. However, the same set of problems would apply in some degree to iOS. The problems come when the apps switch on power-draining devices like Global Positioning System (GPS), the camera or SD card readers. Pathak and his team found that Angry Birds, spends just 20 of the energy it uses on the game itself. The rest goes on tracking the user’s location and serving location-targeted ads.
The iPhone gets pretty great battery life for a smartphone. However, location services and ad-streaming will have some impact on battery life. Thus, you should consider the idea of buying an app for two dollars instead of falling for a cheap app. Because indirectly, you will be paying for it anyway, even if in a different way. You will pay in terms of wasted electricity and annoyingly short battery life. Some free apps can drain your battery in just 90 minutes.
Source: Cult Of Mac