There are some standards in ghostwriting that you should know about.
1. Most ghostwriters of any quality will NOT write your book for free and count on being paid through royalties on the back end.
2. Ghostwriters usually need to be paid for their time on the front end, i.e. as they write your manuscript.
3. Ghostwriting fees are based on the length of your book and the complexity. This is why the answer to the question, “How much will you charge to write my book?” is always followed by “It depends.” Writing a 96 page book is obviously faster and easier than writing a 240 page book.
4. The usual contract with a ghostwriter requires an upfront payment upon signing, followed by periodic payments as chapters are handed in to you, followed by a final payment upon completion.
5. Sometimes a ghostwriter may also ask for a royalty based on sales or a bonus if the book sells more than X copies or makes it to the New York Times Bestseller list.