How expensive are free smartphone apps?

Proliferation of data-enabled mobile devices has fueled the popularity of smartphone applications (apps) at a rapid pace, and the trend is likely to continue for the foreseeable future. Along with the increase in popularity, the characteristics and concept of paid apps and free apps is also changing. In general, paid smartphone apps generate their revenue simply from the cost of downloading the app. On the other hand, free apps rely on advertisements, and/or virtual currencies, for their revenue generation. There are several variants of these generalized approaches. In this work, we focus on identifying the overhead traffic that is generated by the free apps with respect to the paid apps. The overhead traffic is not associated with the operation of the app itself and thus should not impact the usage experience of the apps. Specifically, we consider advertisements, and the transmission of analytic data, as the main components of overhead traffic. With the gradual disappearance of unlimited data plans, the overhead traffic does not come for free. The goal of this paper is quantify the cost of the overhead traffic of the popular free apps and compare it with the paid apps. We have developed an intricate methodology for identifying and measuring the bandwidth requirements of the overheads associated with the free apps. Through comprehensive measurements, we have shown that in most cases, the paid versions of the apps will indeed be a fraction of the cost to the end users when compared to the actual cost of the free versions.