If you have a steady influx of new users, you can further your work by adding them to Subscription automatically. If you run out of Subscription seats, the system will purchase additional ones according to your specifications. Please follow the steps illustrated and let us know if you run into any trouble.
How to enable Subscription automation
Start with Group based Automation in section Automation Features:
Then enable G Suite synchronization (you should have this already enabled for the correct Subscription function, but check it as it's a necessary step):
Now go to Subscription details where you can set your daily spending limit and warning threshold to have your spending under control.
You don't have to enable the Automation for all your users, only for certain User Groups.
You have now successfully set Subscription automation for your users and saved yourself a lot of time and hassle in the future.
Note: The Automation doesn't reveal and process Send as addresses, you need to add them to SignatureSatori manually before they'll be handled.