Technically not even buying, but FitoTrack is a great alternative to many proprietary (american) apps
Technically not even buying, but FitoTrack is a great alternative to many proprietary (american) apps

f-droid.org FitoTrack | F-Droid - Free and Open Source Android App Repository
A privacy oriented fitness tracker

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You can track many sports like running, walking, cycling, swimming,skiing or rowing and also fitness-workouts