Tough question because it varies from one writer to the next.
For straightforward books and eBooks on self-help or general info, a comfortable range is $25 – $75 per double-spaced page (DSP), 12-point font, Times New Roman.
Research-heavy or interview-intensive books warrant $100 – $200 per DSP. Or more.
A publisher-assigned celebrity book can easily yield $250 per DSP or higher.
Of course, some ghostwriters charge as little as $5 per page … or less. Either this is a side income for them, or they live in a place with a lower cost of living, or they’re new at this and aren’t sure how to charge and get more.
Bottom line — there’s a wide range when it comes to what ghostwriters get paid, just as there’s a wide range in skills, style and experience.
When you set your fees, consider what’s comfortable for you and what you can live with.
Here’s a perspective on per-project fees, from WritersWeekly.
This article, written by ghostwriter Michael Arthur Moore, offers additional considerations.
Another way to look at what to charge is to figure out how much you’ll make on a daily basis. If you can consistently make $200 or more per day, you’re doing great.