Why, after I bought a course, am I asked to pay again when I try to view it?

If you are logged out or logged into another account, the site doesn’t know you purchased the course.

For a course at courses.macmost.com, you need to be logged into that site and logged in using the same account ID (email address) you used when you purchased that course.

For courses at Patreon.com, make sure you are logged into your Patreon account. If you are not logged in, then Patreon doesn’t know who you are and doesn’t know you bought the course. Also, if you are logged in, check to make sure you haven’t logged in with a different email address or using one of the “Continue With…” buttons. It is common for someone to accidentally create a second account and be logged into the wrong one.