You're just mad man!!! 300 articles monthly and $150 for those. And you need a native writer!!! What the F**k you're talking about??? Screw you!
At 50 cents per article, which would probably take at least an hour to write, you won't get a decent quality writer. You'll get a non-English writer, recycled articles or robot written articles.
You realize that you'll be paying 1.50 an hour? That would be illegal were you a proper employer but its still highly unethical.
Well if you find such native English writer to work for that amount (for real), I may post a similar offer ... Though I'm not sure I'd be able to sleep at night knowing that someone is working his ass off for a few cents.
They're too stupid to let go, see if they have cousins. At that rate I am sure all 45 of them live together....