How to properly structure tables for a subscription system?

Question

JavaScript

There are teachers and students, teachers buy a subscription at monthly rates, students also. The difference between students and teachers is that students buy one-time and the duration of this subscription is a year, and teachers monthly.
I can roughly imagine how, but would like to read from you how you would implement it. It would be desirable to read the competent variant of implementation.

Answer 1

Keep the beginning and end of the subscription period, and let them buy at least daily.