One model of monetization for a Google Addon is to allow a certain number of free uses before restricting that feature. This post shows one way to restrict a feature in a Google Editor Addon sidebar.
John McGowan is continuing his Google Workspace Add-on development tips at pace. You can read the story so far on the Automagical Apps Blog. In the latest post you can find out how John uses the Properties Service, to record the number of times an account has used a feature in your add-on by communicating between the sidebar and Apps Script using google.script.run. A reminder as well that you can see how you can boost User Property read/write with the SpeedStore library.
Source: Restricting the number of times to use a feature in a Google Addon Sidebar | Automagical Apps Blog
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.