Content writer required

I need regular and totally unique keyword related articles writing about a specific subject Each article needs to be a 500 - 550 word article using specific keywords to enhance a specific websites SEO. Each article must have correct grammar when using 'Keyword Placement' and also be 'Keyword Rich'. Each article produced must be considered as 'unique content' on any internet search engines. All copy submitted will be screened through COPYSCAPE for Plagiarism. Any work submitted that isn't unique content or it is something that has been put through an article spinner will not be paid for. 2$ / per 500 words to my previous content writer , so i'm looking something around it.