How much do freelance writers charge for writing posts?

goldNow that our little site is doing well, freelance writers are approaching us and offering their services. I thought I’d offer this to give you all an idea of the rates per post and per article we’re being quoted.

By the way, the writer who sent this was very professional, had a great portfolio and recommendations from satisfied clients.
‘I offer a fixed $500 monthly and deliver 20 posts/articles a month (5 new posts each week) if the requirement is purely for content writing.”

Another approach was:
“for $500 a month I can write 16 posts/articles a month + bookmarking these on Digg, Stumbleupon, Mixx etc.”

The advantage of this is that it’s a combination of content and a basic amount of promoting the content through social bookmarking and posting them to some other sites you may like these posts promoted on.

How much do you charge for writing posts?