First of all $150 for a 750-word article would be a good payment. Assuming you aren't asking for more words than that ("blog post" suggests no), you can have your pick of people.
Second, evaluating writers is the simplest damned task in the world. Read their frigging code.
Third, average reading speed is 200 words a minute, so you could read an entire submission in less than five minutes. Practically speaking, you would probably need less.
Elance and Odesk merged and are now called Upwork. If you posted the job (number of articles, average length) and asked them to send you sample pieces and an online portfolio, you would be overwhelmed.
Even if you insisted that they have a verified business address within 50 miles of Manhattan, you'd still have a fire hose to drink from.
I wouldn't entirely recommend Craigslist, but you can find a lot of people there-- some of whom are very good and still struggling to make ends meet-- if you don't mind swatting away the 8-balls who will apply (CL gives you a custom email for replies, so you won't deal with them forever.)
Writers tend not to hang out there, but Behance or Dribble do have some.
Let me close by restating my opening. Some questions that get posted here are difficult to answer; others have expectations are ridiculous. But the thing every freelance writer wants most is a steady stream of assignments that lets them make a pretty good income per sale.
Four posts a week at $150 would be $600, which is $15 an hour-- enough to pay bills.
Your request is comparable to posting "I'm a supermodel who really enjoys having sex with men with small penises and no social skills. Can anyone on HN help me?" Your big problem would be people thinking you must be a scam, because your request sounds too good to be true.
UPDATE: There are, by and large, two broad types of writers: extroverts who promote themselves capably, but might or might not have equally good skills, and introverts who lock themselves away and aren't great at self-promotion.
The first group is pretty easy to find, but often not worth the price. The second group takes some hunting but can give you better results for less.