Write Articles and Blog Posts for my site (PART-TIME JOB)

I want freelancers, who can do regular article and blog posting on my site. The site is related to the following keywords, and I would be needing articles on the same. 1) Marketing (Online and Offline) 2) Advertising (Online and Offline) 3) Work at home topics All these fields combined result in a variety of options, so you can never run out of content to write on. For example, even for Affiliate Marketing, you can write atleast 10 articles. 1) I would be needing 2-3 articles every week of around 500+ words, so that is like a maximum of 12 articles every month. 2) The writer should make sure that the articles are completely SEO friendly, and written keeping in mind the keyword density and everything. 3) Should be able to pull images from royalty free websites, since the writer would be directly working on my website, so they need to do it perfectly with images and everything. I would give them a run through on how its done. My budget is around $60 for 12 articles every month perfectly formatted and written directly on my website. if the work done is amazing, I would bump the salary as well. Thanks