There is no average pricing for any style of editor. Always, ALWAYS inquire and get quotes in writing. As with most things, you get what you pay for. Someone willing to edit your 50K novel for under $250 is nine times out of ten, a fraud. Heck, be suspicious of any quote under $1000 for a novel manuscript.
Some editors charge by the hour. Some by the word. Some by a combination of both. Get a quote for the whole job. Ask what types of editing they plan to do. Get their definitions for those types of editing. Find out their experience. Call their references.