Hi,
Apologies for the confusion.
You don’t have to purchase Migrator. UpdraftPlus Premium package already includes Migrator add-on and it has unlimited licence. As part of any of the UpdraftPlus Premium package you can install this independently and activate in as many sites as you want.
To activate the Migrator only, follow the installation guide to Step 4. At Step 4, find the Migrator entry in the Premium/Extensions tab (rather than the ‘All Add-ons’ entry), and follow the activation link for Migrator. UpdraftPlus will then prompt you to update and activate Migrator.
Regards,
Bryle