I've been doing developmental editing and some ghost writing freelance for several years now and don't charge nearly as much as they list below... check out my profile on oDesk:
I charge a flat rate on a sliding scale or $20/hr through their time-tracking app, where they get $2/hour and I get $18.
The downfall to using someone like me is that I don't have an English degree... so if that's important to you, as it is to a number of people in the "literary snob" classification, then don't bother looking on freelance sites. BUT if you're an indie author, there's no reason for you to pay out $2k or more for an edit.
And on the freelance site, I'm sort of in the "middle of the road" pricing range. I also have experience with editing, with a number of books and other materials under my best already, wither as hired work or as part of the publishing company I own.
My process, that way there's no confusion as to which type of editing I'm speaking of (I charge around $300-$1500 depending on the extent of the editing; for most people, it's $300-$500 based on how long the MS is).
I do an initial edit for technicalities, awkward sentences, and to get a feel for the story as well as catch glaring errors in plot and timing. Once finished with the first pass, the MS is sent back to the author (that would be you) for approval as well as learning and clarification of questions I had (not to mention fixing specific portions that I maybe didn't due to the sheer amount of rewriting necessary, as maintaining the author's voice is the most important thing). The author sends the MS back to me, I do another pass, searching for essentially the same problems - syntax, awkward sentences, repetition of words or phrases, and so on and so forth. I also take a special interest in punctuation and its appropriate uses... many people have ellipse or comma addictions that absolutely have to be brought under control =).
I don't know how much others charge, but I'm willing to bet that those charging thousands either have worked or currently work for a more major publisher in NY, which could very well add to the price. I charge what I do because indie authors are more likely to afford it, and they are the ones who really need the editing help from an independent source.
Hope this helps - if you need an editor & like my editing style/writing style, just let me know =).