Reliable Zoom-like program for online meetings/classrooms?

Famous Blue Raincoat

I'm setting up a website which needs to have a reliable program to ensure online classes can proceed on it. What sort of technology would be best for this? The budget isn't big but I appreciate that this is not something that can be unprofessional. Could Zoom suffice? (when does that stop being free?)

Also, what sort of features should I ensure are in this? E.G. a 'waiting room', a log-in feature where only people who have paid can access, a feature to remove people, etc? The website needs to be able to do two main things: give classes online reliably and, second, have a secure payment feature.

I'm using the Wix website builder (unlimited/paid version). Thanks a million.