starry_eyes
You can store data online via the Garmin connect app, or store everything locally with Garmin Express. Lots of people also use the gadgetbridge app as an alternative. But regardless, Garmin let's the user control all their data so you're good.
Devices are priced across the spectrum depending on the use case. You're best bet is to just search their website and filter your use and check the features. So as examples; the Venu is the most Apple Watch like for features, the Forerunner is popular for running/fitness, and Instinct is rugged. There's lots of versions within each model line, and other model lines that are less expensive and vastly more expensive.
Garmin runs sales multiple times a year as well, for used watches you would just check reputable retailers. Their watches do last a long time as well, easily matching/exceeding the 7yrs of updates the current GOS Pixels enjoy. If not longer.