I may have to assume that the answer is "not very" if another day passes without an answer.
The way I look at it is if it costs only $15 and you charge $.99 per copy ($.35 per copy royalty), you have to sell or have a sales volume increase of 43 copies to break even. You also have to hope, not count on, that you have carry-over into the future from the exposure and that you have produced a book that people will want to read, hopefully when you raise your price to what you think or know it to be worth.
A forum community dedicated to Amazon Kindle owners, authors, and enthusiasts. Come join the discussion about publishing, audio, troubleshooting, models, styles, reviews, accessories, classifieds, and more!