Have you ever heard of Scrivener? Joseph Michael created his first online course teaching people how to use this niche software product for authors three years ago. Today his Learn Scrivener Fast Community has over 17,000 members. You do the math. 17,000+ members at $297 each isn't bad for a “set it and forget it” home study course.
Here's a free ebook from Joseph outlining his Easy Course Creation methodology. No opt-in required. Just click the image below for free access.