Finding quality writers can be like looking for a needle in proverbial hay-stack. Check-out our service it might suit you. You can buy pre-written, original articles. The price point you suggested is perfect. Best of luck with your quest
Check out getmyposts.com iWriter is okay too but they are pretty expensive. It does also depend on what quality you are looking for. If you need super high quality content that is very well researched you are probably best off hiring somebody and working directly with them.
Since you are offering a fairly good price I would try google blog search and see if you could find blogs like yours and ask the blogowners if they would like to make a guestpost for your site. Some of them might even do it for free if they just get a link or two in return. Remember also to set up Google alerts so you know whats happening in your niche... Good luck
TextBroker.com is an amazing website, they can get it to you for 15 bucks, way cool site. go with them, and fyi- i dont work for them or have any affiliation with them
Have you tried iwriter.com (cheapest way and should be good articles too)... keep searching on freelancing websites like guru.com or elance.com take good notice of freelancers ratings/reviews and always provide exact and accurate description of what you're looking in a writer so you attract the right people...