Hmm I don't know if you are a writer, a designer or a coder. But since you said per word I'm gonna assume you're a writer. I always work out quotes. Just remember to get everything in there.
lets say 2 hours research for something.
then the time to write or whatever you do
Then everything else: light,paper,coffee etc. (you decide how much you put in this)

Then work out how much you need per hour and how many hours it'll take you.