Content Writing / Article Writing

I am looking for content / articles on a range of topics. Topics will all be product related. Articles / pages are to promote a single product type, for example "Dart Boards", "I Pods", "Bicycles". One or two articles / pages per topic. 500 words+ per page. 5%+ keyword density. Informal natural tone. Native standard English (US preferred). No duplicate content, must be 100% original in search engines / copyscape. Please quote price per 500 word piece. Please provide links to examples of your work. Please indicate turn around time. Ideal candidate would be a US based blogger. Thanks