Read this article from Web Promo.

“1. Why give away what you could sell?

That’s a fair enough sort of question. If you write an ebook or report then surely you should be paid for your sharing your knowledge with others. But if you put a price on your work, especially if you are not yet recognized as an expert in your field, you will probably find your work being overlooked.

Why not make it freely available to anyone who might be interested in your topic of expertise & promote yourself in the resource box you put at the bottom of your report. Allow it to be reprinted as long as your resource box is included.”