The short version, until the long version is written.
SadAnalytics Pro is not on sale yet. When it is, this is the plan.
A SadAnalytics Pro license will cover one or three WordPress sites for one year of updates and support (or month by month, if you choose monthly billing).
If Pro is not for you, ask for a refund within 30 days of purchase and you will get it.
When a license expires, Pro will keep working. Your numbers will stay live and the sync will keep running. Updates and support will stop, and the Pro actions that add, change or export data (CSV export, manual add/edit/cancel, CSV import, Mark paid, Access changes) will stay locked, with a "renew to unlock" message, until you renew. Deleting a manual record will still work.
The free plugin is GPL-2.0-or-later software, and SadAnalytics Pro will be too.
Questions about any of this? Email [email protected].