Baby Feed Timer does not use subscriptions.
Baby Feed Timer offers a free 7 day trial. This trial is not part of a subscription and at the end of the trial you will not be automatically billed.
Once the 7 day free trial has expired the App will only allow you to export your data or pay a one time InApp purchase to unlock the full version.
Once the full version has been paid for you will not need to pay ever again and are free to use it on all your other devices, both iOS and Android.