The Paytable.io members only area for your subscribers now supports additional sources including the ability to embed Notion content. First make sure you've logged into your dashboard over at Paytable where your can get started for free.
Embedding Notion content Is super simple and works the same as embedding your Airtable base. Using super.so you can basically convert your Notion site into a live public domain that can be embedded in Paytable.
Bonus.. Super.so and Paytable.io both have free plans which means you can effectively start selling access to any Notion (or Airtable) access in minutes, without paying a penny.
Go to Notion.so and create an account
Click share to web on your Notion page (use a top level page if you want to include sub pages) and copy the Link.
Click add new site and add its name and the full url of your notion site or page.
Then super will auto generate a site for you.