At least in theory there is a way to reap the benefits of the connectedness without that price, if the system relies on a local computer instead of someone else's, running open source in both ends. I actually remember reading about a system like this somewhere; if I can recall its name* (as the underlying tech doesn't interest me directly, for me it's just a "meh why bother?"), I'll post about it here.

*EDIT - as another user pointed out, it was Home Assistant.