What an editor does is discover your characters, your situations, and your images without seeing any of the creative process that brought them to life. Where you might see all the crossings-out and labors, all the accidents and decisions, the editor sees only a page. This is the clarity you need, and you can never achieve it for your own writing, simply because you envisioned it first. The editor will tell you what an attentive, an educated, and, most importantly, a new reader will experience while reading your book.

Stephen, you’re right, and I think much of the confusion about editing and its pricing stems from the fact that editors offer a range of services (in addition to a range of experience). It might be best to view editing on a spectrum from broad (developmental) to detailed (copyediting and proofreading). And it’s always best to have as clear an idea as you can about the kind of editing you believe you need.
We may be talking about different services. I’m referring to a full read that usually creates a 5-10 page edit letter–no in-line editing. Or, perhaps we’re just working in different corners of the market. I’m around those who are freelance editing pre-query for writers hoping to traditionally publish their genre fiction, not the kind of rigorous editing a self publishing author would need, which should rightfully be much more expensive! It’s true that most people doing freelance editing at the lower rate/rigor aren’t doing it full time. It’s an optional step for those traditionally publishing, and the prices reflect maintaining access for those writers, I believe.
EFA has an excellent reputation in the field, and their high annual membership fee keeps out the riff-raff and newbies merely flirting with the profession. For writers, EFA also has a very useful rates survey for the different kinds of editing, helpful for anyone shopping around: (the-efa.org/res/rates.php) For those keen to find a fully vetted editor, try Editcetera (editcetera.com). This group not only tests every applicant, they also supervise for a full year. Of course, their rates are higher. Another highly regarded editorial organization is Bay Area Editors Forum (editorsforum.org), with a searchable database of editors. I’m a member there.… Read more »

I cannot speak for all editors, of course, but I know I and many of us would be open to editing just part of your book at first, say, a particular chapter or two that you sense needs a lot of work. That is often enough to show you mechanical errors that you tend to make repeatedly. You can then go through the entire manuscript yourself looking for as many of the same kind of errors as possible. You will sharpen your basic writing skills in the process, and it will pay off in all future projects.