how expensive is it to get published?

Depends

Publishers pay YOU not the other way around. They also do the editing.

If you have to pay anything to get the novel published then you're dealing with a vanity press which is basically just a printer that makes copies of your book and nothing else. They don't get it in bookstores and they don't market the book, they just print it up and send it to you. That is NOT the way to get published.

It isn't. The author gets paid by the publisher.

Its not necessarily money as the editing.

Commercial trade publishing costs the author nothing.

Self-published authors sometimes spend the same, but their product is often worse for not having multiple rounds of professional edits, "real" cover art, and of course skilled promotion.

It doesn't cost a dime.

Hiring a printer would cost money, hiring an editor costs money, hiring a ghost writer costs money, but normal publishers pay the authors an advance.