I use them myself for article directory submissions.  Need-An-Article.com only costs $9.95 per month for membership plus the cost of your article, which varies by word count, but all extremely inexpensive (see prices below).  I don’t know how they do it, but glad they are.  You’ll have a long list of writers to choose from, some with writing samples.  I’m very, very picky about writing and always make some changes, regardless of who writes it – even if I’m the original writer, LOL.  Included in the price per article is the ability to ask for revision(s) if you’re unhappy with something.  Even that might not be enough if it’s the wrong writer for you.  I’ve gone through a number of them to find the few that works best for me. For the cost of an article,  a writer that doesn’t work out for you won’t be an expensive mistake.  With this writing service,  you own the article and can re-write it to your heart’s content to avoid content duplication, or at their low prices, pay them to re-write it.  They offer tutorials, and reading through the site will help you understand how it works and what the abbreviations mean, such as UAW (Unique Article Wizard) below.

Articles
550 words – $ 5.52
750 words – $ 9.03
1000 words – $ 12.50

Blog Posts
100 words – $ 1.75
200 words – $ 2.75
300 words – $ 3.75

Rewrite options
UAW 650 – $ 10.00
UAW 1100 – $ 12.00
600 words – $ 4.75 (Pkg1)
1000 words – $ 5.75 (Pkg2)
Single Rewrite – $ 6.75 (AR)