I am a very experienced writer, with 2 published books (translated into multiple languages and sold in several countries). I was shortlisted for the Faulkner-Wisdom writing award, have a degree in writing from the University of Texas and dozens of published articles. I am currently writing an article for the Atlantic Monthly. I'll be more expensive than others because I'm highly skilled with a solid background.
I've also studied marketing copy (Ultimate Sales Letter, Cashvertising, Copywriting secrets, and Mad to Stick among others), so I know how to stuff that pulls. I'm not sure what the specifics of your project are - how many articles a week, how many total, etc., so it's tough to bid, but I can go as low as $35 per article and deliver good quality to get you top sales.