Companies I work for pay freelancers $750 for a 3 page article for industry trade magazines.
An average blog post should fetch up to $300
Really, the price is determined by your reputation and results. I have never heard of anyone paying "per word", perhaps if you are Sugarman you can get that. The rest of the world just gets set payments for expected content length.
You can try looking at Mechanical Turk
www.mturk.com and see what they are paying for blog post. Might be a good place to make industry contacts.