I've been given a project by a digital agency to edit the copy for an ad compaign and am not sure what price to quote (so far I have exclusively written website content/blog articles etc). The campaign is for a very large international cosmetics brand; the agency is Hong Kong based so require my skills as a native English writer to provide copy that is gramatically correct etc. I helped the agency win the pitch by editing the copy in their presentation so they have offered me the work. It will entail editing the copy for the site campaign pages and 20 social media posts.
What would be a sensible price for this? Grateful for any advice!