Second hand kit? Aren't
you and your
goals of
self improvement worth
more than that? ;-)
I do agree on costs, though. I'm a pretty keen cyclist (outdoors) and dabble in running. I have tried various fitness apps like Strava out of curiosity, even played around trying to analyze my own gps traces in Jupyter to figure out my aerobic threshold. But I don't see any of the apps as worth paying a subscription for [1].
[1] Except maybe trailforks, if I'm on holiday in an area I don't know that has unofficial mtb trails well documented on that platform. But now they've made it proprietary I'm far less inclined to contribute my own trails to the database, so go figure.