7500 words single spaced is around 15 pages, whereas 7500 words double spaced equals about 30 pages. This means that it takes around 2 hours to write a book of 100 pages. The first 5 chapters are usually the most difficult because they have the most content so you need to give them your best shot. The rest of the book comes much easier once you get into a writing rhythm. You can write one book per year if you want to. It's completely up to you! As for price, this will vary depending on how professional you want to make the book and what kind of publisher you choose. A basic book with nothing more than chapter titles and page numbers cost around $10,000 - $15,000. A more advanced book with diagrams, samples, and full illustrations might cost up to $20,000. Large print versions, audio books, and other adaptations can all increase the price further. But even with all these extra costs, writing a book is still cheaper than publishing one! The time it takes to write a book also varies depending on how experienced you are.