There are a number of editors’ associations found on-line and off. If you would feel better about going through such a body try The National Association of Independent Writers and Editors (UK) or the Society for Editors & Proofreaders (UK). In the US there is The Editorial Freelance Association .
Otherwise, editors with whom I have worked or come across personally are listed below, together with current prices ( these were correct at the time of writing, in November 2017, but please visit the individual web-sites for up to date pricing information ).
Roz Morris – Nail Your Novel Consultancy Full manuscript critique £19.50 per 1,000 words, minimum £390. Copy/line editing in line with SfEP rates. Roz is my current editor and I cannot praise her enough!
Stuart Wakefield – Developmental edits only, works at Victoria Mixon ( current rates unavailable ) Stuart did the developmental edits on ‘The Village’ he was great.
Victoria Mixon – Developmental edit $0.08 per word, copy/line editing $0.10 per word, full developmental, copy, line etc. $0.18 per word
Sarah Kolb-Williams – Full manuscript edit ( mainly science fiction ) $0.10 per word, copy/line editing $0.03 per word
The Literary Consultancy – Full manuscript £1.75 per page ( but see site for details ) Copy/line editing between £0 and £60 per hour.
Stephen Parolini – The Novel Doctor – Editorial review from $750, Comprehensive Edit from $2,000.
There are more famous, bigger concerns, below are three very different service providers.
Bubble Cow will give you a free ‘sample edit’ of your work.
Bibliocrunch is a ‘matching service’ putting authors together with editing professionals and other services.
Formerly a classic review service Kirkus now provides editing services to independent authors