One of the best places to look for writers is Problogger. It costs you $50 to post a job but you will find one of the best talents over there.

You can hire great freelancers on oDesk and Elance but you need to know how to search for them. They will cost you less for sure. Look for people who have written in your specific niche and ask them to write you a post or 2 to see what they are capable of.

Right now I'm teaching people especially about how to find, hire & manage freelancers. I have hired more than 100 freelancers so far so If you want to learn more about how to do it, feel free to schedule a call.