Thank you for the insight - I actually suspected there is a lot of couponing and so on going on. I guess like in the iOS or Android app store (or presumably all markets) people try to game it. I would probably do the same and try to sign up free subscribers until I have 1K or so to make my course look good.

But don't worry, I am genuinely interested in creating such a course, and I don't want to rip people off. I plan to have fun while making it, so there is not much too lose.

Actually I had decided recently to try to write ebooks as a means of learning stuff myself (in that case it was AngularJS). I think of it as an additional motivation and I think it could work for me, if not for everybody. Making a video would probably be supplementary to that.