I teach English
and make something like 25$ an hour (The pay scale at my particular job is a bit wonky so it fluctuates a bit). Didn't need a degree or a certificate of ability to teach English
or anything like that. That being said, it does take some experience to get and keep students. I've been at it 2 years and am just starting to get to the point where I can usually lock my students' interest in and be sure of having them come back for more and more lessons.
Teaching isn't really a skill you can learn from a course IMO. A teaching course wouldn't hurt but they're often not worth the money
they cost unless you're teaching in western Europe
or one of the other rare places where such a credential actually has any value.