Simply put, $50 is incredibly high for an eBook — particularly when the site itself hosts a large quantity of that information for free.
We think more along the lines of the Picasso Principle: http://www.psychotactics.com/blog/the-picasso-principle/
The Stack Guides greatly simplify the process. They are NOT for everyone. But for the layperson who doesn't have the time and/or energy to figure it out themselves, it's well worth the investment.
Simply put, $50 is incredibly high for an eBook — particularly when the site itself hosts a large quantity of that information for free.