The iPhone isn't lacking in data usage trackers, but many of them offer few features or do little to ensure they're tracking your data accurately. We like Data Usage because it helps keep you on top of all the data you're using, alerts you as much or as little as you want, and provides in-depth statistics. Platform: iPhonePrice: $1 ($2 for Pro)Download Page Data Usage is a very thorough app. Unlike most of the other apps on the app store, it ensures you've set it up correctly when you launch it. The...