This is an awesome question!
My name is Humberto Valle, I'm a co-founder at Unthink Digital Marketing a small hybrid digital marketing agency in Texas. We have been helping small businesses for the past 10 years with their marketing efforts. I'm an MBA with several successful ventures and have personally coached 3 new business owners reach $2million revenue mark, one of them from just an idea.
To answer your question, yes you can expect some sales but I honestly wouldn't count on it. There are many self published authors out there and the chances of you releasing and selling are slim. You might sell to friends and family - but you would have to ask them to do so right? So think about it this way, if you don't ask your Friends and Family - would they on their own find and want to buy?
Selling a book is not that much different than any other service based business, I will add a link to a relevant article at the bottom of this answer. A book is dependent on the author's clout and notoriety - how well known is the author and how good will the content be for me?
What I would suggest doing is as follows:
1. Have landing pages with FREE sections or chapters of the book.
2. Have landing pages for each offer and trade emails in exchange for a chapter
3. promote content and ideas covered in your book on your twitter, facebook, and youtube.
4. have a website with strong SEO so that you can promote the book organically (self-sustain) through the website and link the various landing pages for free content.
5. publish the book and continue to promote through social channels, and through the emails you have collected.
If you have already published the book, this process wouldn't change much but the wording and type of offers could.
Obviously each of the efforts on their own require some sort of strategy or best practices so that it actually helps you sell and not just waste time online but the general idea of what should be done is pretty straight forward.
I hope this brought some clarity to you, my name is Humberto Valle and through www.Unthink.me we can help you build and promote the right content to generate sales.
What is Inbound Marketing And Can It Help My Type of Business? http://blog.unthink.me/what-is-inbound-marketing-and-can-it-really-help-my-business