Look at the front and back of the next page for acknowledgements. If an author worked closely with an editor throughout the writing process, they may choose to include their name in the acknowledgements page. The acknowledgements page is usually a few lines of text centered on a blank page after the copyright information. Read it to see if the editor is mentioned.
When you get that email, particularly if it's your first book, make sure you are well-rested and in a positive frame of mind before you open it. If it’s your first book, the editing process will be hard on your ego, but remember, the editor’s job is to make your book better and help you learn the craft. You are paying for them to give you critical feedback, not to pat you on the back and say ‘good job.'
I was going to tell Blake that his figures are actually a little low. The EFA uses lower prices than Writer’s Market (which is what I use as a starting point for my pricing). Two tenths of a cent (.002) per word? That comes out to $100 per 50,000-word book. It’s a rare editor who can accurately process 50,000 words a day, so that would be dooming an editor to living off of about $50 a day. If an editor is earning such low amounts per book, then one of two things is happening: that editor has someone else to pay the bills (thus not needing a real income), or that editor is blowing through books far too quickly in an attempt to earn enough money to survive, and is leaving errors—in which case it’s pointless to hire that editor. Undercutting on prices is unethical and it hurts everyone in the industry. I would not trust that editor. Anyone who pays such low prices is exploiting another person, which is also wrong. Authors, be prepared to pay fair prices. Editors, charge enough to survive and don’t undercut the industry standards, because you’re causing harm to everyone in the field, including yourself.
I’m sorry you feel that way about my participation in the discussion and defending editors of similar background to myself from what I considered unwarranted disparagement. Perhaps the only approach that would have 100% proof against accusations of “trolling” would have been to allow the claims to stand unchallenged, but that did not seem fair to people who come here to get useful information.
Another online editing service is Scribendi, which has over 300 experienced and educated editors. They've been around a long time. With this service, you decide how fast you want the book edited and how extensive the edit should be, then they match you with an editor. You don't ever actually meet the editor, but rather work through their customer service team. Their prices depend on your requested turnaround time and word count. You can get a free quote here.
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.