First-time authors and small publishers whose hearts are pure and whose motives are saintly assume that the whole publishing process works on trust and everybody is happy. The truth is, the publishing process works on contracts and most of the players aren't happy unless they are taking pills. But newbies to the business are almost afraid to ask about the price, either for fear that it will expose their lack of experience or because they think it's just not done that way. In consequence, I hear from plenty of new publishers who blow their whole production budget on a cover design or an edit, and who have nobody to blame but themselves.
I've never heard of a publisher ordering up a print run of books without inquiring what they will cost, but that seems to be the only production cost some new publishers include in their book budget. The most I've spent on the complete book publishing process (not including printing) is around $2,000, the least was around $400, when I did everything myself, except for a light edit and the proofreading. I know a couple self publishers who are capable of doing the whole job themselves, including proofreading, but first time publishers should at least run their text by an outside editor to get an opinion on suitability for publication. Whatever work you decide to contract out, be it editing, design, legal work or even (please don't) publicity, make sure you agree to the scope of work and the price up front.
I've never done a fancy written contract for work I outsource, but I always get the basic terms in writing by e-mail. I don't know that this has any more legal value than a verbal contract, but at least it's better than arguing whose memory is better. If you agree on a flat rate for a job, make sure you agree on a schedule as well. Publishers who just assume that an outside contractor will work on a job full-time until it's done are in for a disappointment. If the book production schedule isn't drawn up by experienced professionals and agreed upon, it's unlikely to be kept.
Your main budget items for producing a self published book will be the editing, interior layout, cover design and proofreading. If you are doing your own layout and cover design and using print-on-demand to avoid up-front printing costs, there's no reason you shouldn't be able to bring the book in for under $2000. But what's more important than the final cost itself is how that cost fits your business model and your budget. If you've done your homework, you should have a realistic idea of how many books you can hope to sell over a couple years, and how much profit you can expect per book based on your distribution and production costs. If you budget more money for the publishing process than you can realistically earn back in profits, you aren't running a business. The goal isn't to break even, it's to come out ahead and earn a living. So don't dig yourself a deep hole by operating without a budget or identifying your costs before you incur them.
And that's the theme of today's publishing video: