A: Hello Chris!
Thank you for your interest.

We have the Firebase Authentication for login option.
You can create a Log-in page in your app with Firebase Authentication option.

Here is a guide https://drive.google.com/file/d/1gEwQAhHZye5rEiblQHANtDM1KP0a8EcF/view

And a video tutorial too https://www.youtube.com/watch?v=NKb3qdVu9DA

Paid content feature is available both for Android and iOS. You can lock one of your app component with its content for paid access so users will have access to it after the payment is made.

Regards