Hi ldspclaw
welcome to this Apple (user-to-user) Community!
Re: "How can I publish my book on iBooks without giving it away?"
How will you arrange for the collection and payment to yourself of the purchase price ?
Am no expert in this area, yet your request to the community deserves some response.
If you don't have one already: Seems you would need to set up an iTunes Connect account ?
See: Publish a book to Apple Books in Pages on Mac - Apple Support for details.
Eg: Above article also says:
"Your book must be reviewed and approved before it’s available on Apple Books.
You can check the status of the book in My Books on iTunes Connect.
For more information about publishing to Apple Books,
see this Apple Support article
or
Apple Books Formatting Guidelines.
For information about writing, publishing, marketing and selling your book on Apple Books,
see authors.apple.com."