In answer to the 'how expensive is it to write a book' question, it's similar to 'how long is a piece of string'.
Writing a book only costs the price of a pen and paper.
Typing the book costs the use of software, computer and electricity.
Publishing....? Well, you can upload an E-Book for absolute pittance (if not completely free, depending on the website. Amazon costs money I imagine)
If you want it published into an actual tangible object, you can self publish a tiny amount (probably in the hundreds) for a reasonable cost. They would be terrible quality and feel extremely cheap.
Or you could crowd fund for something that looks nicer and is printed in the 1000s...
Since crowd funding isn't going to go anywhere, I would predict he 'publishes' his next bible in E-book format. Then uses the funds he think he'll get from that to finance a small print run. Maybe he'll offer signings or other perks to try and scrape together some more pennies.
Regardless of what he goes for, it will not be the pot of gold he thinks it will be.