Also, you might want to invest in some e-book authoring software to protect your book, rather than just using a pdf and having someone take your book and give it away, or better yet sell it on their own site!
This software will also often allow you to put music, video and other such computer enhancements in your ebook rather than just straight flat text.
I wouldn't go charging more than 15$ for it unless it has something you can't get anywhere else. Not many people will be willing to shell out 50$ for another self help book.
$50 will buy you
several books from
famous authors. You will need to provide a good reason why yours is worth $50 for one from an unknown author.
Also ebooks are free to make and sell so you need to really have a good reason because you can pick up a paper copy of a famous PD book for 15 or so dollars which costs money to produce, market and distribute.
$10-15 though, is nothing for most people and many will buy it just to give it a go in case it happens to have something useful.
GET IT PROOF READ. If not by a professional then by someone who at least studied English in University.
Get good sales copy on your site. Find a pro sales writer for this if you can. It might cost you money to get it but good copy = sales , bad copy = tumbleweeds.
Get someone with technical
and marketing skills to build your site. Not just one or the other. A site that looks good doesn't necessarily sell, but nor does one that users can't figure out.
Alternately, write your book and get some pros to help you with the rest.