My standard rate for academic proofreading is as follows:
£16/1000 words, with a 10% discount for all documents over 20,000 words.
For proofreading and copy-editing on other projects, I am happy to provide a quote based on the standard CIEP guidelines for freelance copy-editors and proofreaders.
I also offer the option of payment by instalments, which can be handy if you need me to look over a long piece of writing. Please note, though, that the 10% discount is not available with this option.