You might consider a "micro-continuity" style website. The user pays like a membership site, but it is a fixed number of payments, and they get new content fed out in increments as they pay. So if you can split your content into 6 modules for instance, you could see it for 6 equal payments over 6 weeks, or something along those lines.

Pro -> Less up front commitment than a membership site (assuming recurring billing as long as you are a member), gives you reason to contact users over and over again for the duration of the mini-course, potentially creating opportunities for subtle upsells.

Con -> Cap on earnings, potential for users to cancel before the course completes to try to get whatever guarantee is offered, users have to follow the pace you set, also a little harder technically to setup.

Your call, just wanted to give you another option. As to the choices listed, ebook prices seem to be watered down. If you are very good at writing sales copy, an ebook may still be worth doing, but IMO, if priced right a membership site should give you a better return.