Based on initial impressions I'll agree the book isn't giving off the vibe that it's worth much more than 1-2 coffees of value ($5-$10), but after looking into it a bit more there's no reason why it can't improve that (it is after all a decent length book by a previously published author who has relevant experience, so $25 sounds quite reasonable).
1. Better site design would make me more confident the book is well designed.
2. Include chapters in the same format/design as the book (rather than just HTML pages).
3. Tell me front and center that the book is 197 pages (that's quite a lot!). First impression I thought this was a couple of blog posts worth of generic advice, not a decent length book.
4. Make the links to the successful blog posts that spawned the book more prominent (bonus: site adds credibility).
5. Make it easier on scanning that he's already an accomplished well-reviewed author (Build Awesome Command-Line Applications in Ruby). Include reviews from here initially in the context of showing author credibility (need to make it clear they're not for the current book though obviously).
6. Highlight the experience in an easier to skim way
7. Make the book cover look different, e.g. 3D rotate with imaginary book pages, or border, or on a darker background or something (the white edges for me at least didn't look like part of the book, so I see the slim narrow purple band and think "booklet" not book).
For reference, Nathan Barry does some of the best sales pages I've seen (Patrick McKenzie aka patio11 happens to agree).
Nathan's advice:
http://nathanbarry.com/learned-selling-6000-ebook-today/
http://nathanbarry.com/step-by-step-landing-page-copywriting...
Samples:
