I use only flat fees, no hourly, because I don't know how a client could possibly know how many hours an editor actually works on his or her manuscript. Page rates are based on manuscripts over 50 pages, presented in double-or-space-and-a-half 12-point type in a regular (not exotic or script) font. This comes to about 250 words per page. My basic page rates are $2 a page for a comprehensive edit including grammar, spelling, typos, syntax (the way words are put together) and any errors, like verb/noun tense or unrealistic dialogue. I also suggest changes in wording for clarity and emphasis and make comments that coach you through not only the manuscript I am working on, but that you can carry with you when you write again. The most expensive edits are $3.50 a page, and they are called developmental (some editors call them content edits but they are the same thing). This is an edit that includes all the elements of a comprehensive basic edit and also fixes problems authors do not know how to fix. Maybe there are plot holes, or character development is needed. Or possibly, you just need help creating bridges between chapters or a bang-up satisfying ending. I can edit in American English (which is called Chigaco Style by publishers) British English, or Associated Press (used for magazines and newspapers). Usually I put in a placeholder bid based on your word count until I am more familiar with the job and the client and see what he or she wants. Some people are open to suggestions and some want things done a specific way, so much depends upon that, as I mentioned above. I work in Word with track changes that come back to you first with red-lines through the deletions and blue additions, and with comments. You may opt to keep or change any of these, and then send it back to me to fix your way and I change it to a black final copy.
White papers and synopsis and cover work is still a flat $50 even though they are short.