Here is a deep dive into the VisuStella ecosystem to help you decide where to spend your time (and money).
The confusion regarding "free" stems from VisuStella’s Patreon. Subscribers get to beta versions and "Time-Release" plugins. A plugin released to Patreon in January becomes free to the public in March. Currently, there are no "Patron-Only Forever" plugins for MZ.
To help you decide, here is a breakdown of how the two tiers interact.