My background is largely PR although over years have done increasing about of copywriting work. Recently been asked to quote for an ongoing copywriting job which will require 3 articles (only short - 400 wods) per week. As a PR bod I charge per day but thinking this is maybe not appropriate for this job and I should charge per article?
my copywriing clients charge per fraction of a day for short stuff. Make sure you include the time for ongoing research, plus a bit to cover your general running costs. Depends if you are more productive doing short bursts of things and chopping and changing regularly, or if you write better in long burst focused on one project. Set your fees as high as you think the client will pay . But yes, IME, it's either an hourly or (fraction of a) daily rate, rather than a "per item" rate. Alternatively work out how many hours you need, and quote per item - it really depends on what the client is used to. One disadvantage to this though is that if one pience taked much more work than others, then you're out of pocket.