I was reading an article few days ago about a teacher that made over 1mil dollars selling courses on teacherspayteachers.com.
I made made some research and I found that this marketplace is for teachers wich publish courses for kindergarden to highscool and university and makes some decent cash
The thing is that this is a professional marketplace and theoretical and ethical if you're not a teacher you shouldn't be there... but...
...what if you have the knowledge or you know somebody who has the knowledge..or maybe an outsourcer... to create great content, I guess it can be done.
Teachers are not marketers and if you come with some good products and a good marketing, I think you can succeed.
The only question that remains, is it ethical?