The iOS App Store includes reviews of applications by users. On an iPhone, open the App Store, select Charts, then choose Free. The applications listed are the current top ranked free iPhone apps. Select any app and scroll down the screen to read reviews by users.
This same listing can be reached on a computer by navigating to Apple.com, selecting iTunes at the bottom of the page, clicking Charts, then selecting Free Apps. Alternatively, reviews can be found on a number of third-party websites. For example, TechRadar has a listing of the 55 best free iPhone apps of 2015 with reviews of each app.