As cranklecat mentioned, the Wahoo Fitness App is completely free and you can connect any BTLE sensor(s) to it without having to pay a subscription fee. However, it is somewhat limited in the data that you get after the ride. If all you want is just basic ride information, it's fine and it will automatically send your rides to Strava when your ride is done. However, if you are looking for a feature rich cycling app, you can't beat Cyclemeter for $10.00/year. They have added two features to it that you won't find in any other cycling app that I know of: 1) Interactive Live Tracking; where the person(s) following you can interact with you while you are riding using your phone's text to speech feature and 2) Voice actuated commands where you can start/stop your ride and get get back any bit of ride data you want using Siri. Cyclemeter also stores all your rides on the phone so you never need WiFi or a cellular connection to view your rides and data.