I've had a few questions as to why I just don't self-publish all of my books. Why would I try to go the traditionally published route?
The answer is simply: money.
So, let's take my free novella as an example (which is on the cheap end of the cost curve as a novella is shorter than your typical novel). When I'm done writing the rough drafts and getting feedback from my beta readers, the creative process essentially ends. What happens next is production.
The manuscript will need to be edited. Some people will do this themselves so save on cost - I don't have that sort of ability. There are several levels of editing, some of which go by other names. However, here are the options:
Editorial Assessment - A professional's overall analysis on your book including strengths, weaknesses, style, marketability and so on. In some ways it is a high level Developmental Edit.
Developmental Edit - Essentially, this tackles the overall story, plot holes, structure, and so on. This is a "big picture" go-through of the book pointing out flaws in things like pacing and plot.
Content / Line Edit - This handles spelling, grammar, punctuation and clarity of the text. The editor will make sure that each sentence makes sense, and points out all of the mechanical issues with your writing.
Proofread - Sort of a minor version of a Content / Line Edit, except here they are just tacking things like spelling, punctuation, and capitalization.
For the novella, I will forego an Editorial Assessment and Developmental Edit as I'm pretty confident that the major elements - characters, pacing, action, etc. - are all pretty sound. I'll have at least one round of Line / Content Edits, possibly two. Then, before I go to print, I'll have a Proofread done to finalize the manuscript.
A Copy / Line Edit will cost anywhere from $160 - $200.00 per pass (so, $320.00 - $400.00 worst case).
A Proofread will cost anywhere from $120.00 - $170.00.
Now that the manuscript is tight, it has to be formatted. This is where I'll be able to cut some costs, as the novella will will be fairly plain and generated as a PDF document. However, were I to make it a full book, you're talking a formatting cost of anywhere from $200.00 - $500.00.
I'm not an artist. Doing a search for the costs of cover art, I'm looking at anywhere from $300.00 - $1,000.00. Maybe I'll get lucky and have it done for less, but I doubt it.
Technically, the fact that I've written my manuscript and had it published, makes the story protected by copyright law. However, I intend on submitting it to have the copyright registered. The cost? Roughly $50.00.
Let's say I use Ingram Spark to handle my book. The cost for that: $50.00.
Let's say that I'm going to go the standard self-publishing route (which I'm not for the novella).
Minimum Cost: $880.00 (roughly $900.00).
Maximum Cost: $1,670.00 (roughly $1,700.00).
Expected Cost for the PDF: $920.00 (roughly $950.00).
Those costs are just to publish a professional-looking book. It doesn't take into account marketing, which is an additional expenditure. Assuming that I make $1.00 per book, I'd need to sell anywhere from 900 - 1,700 books just to break even. And that is not even factoring in marketing costs.
Most self-published authors barely sell 200 copies of any book.
Or, I can land a publisher, have them pay me $2,000 as an advance, and roll that into marketing costs. They will also help me market my book, even though I won't see anything until sales exceed my advance. The odds of my book selling 2,000 copies would be good with a company that has a dedicated marketing department (or person).
Mind you - this is my novella. With more words and more pages, all of the numbers I cited above increase.
A self-published book, done right, costs money. Sure, you can do the editing yourself, as well as the formatting (I honestly think formatting is optional), and maybe slap together a reasonable cover. Some people have a talent for that. I don't.