If you opt for cheap freelance writers you won't get the quality which converts. My friends tried fiverr, upwork etc website. Finally when he realize he was wasting his time on freelance portal by hiring different freelancers. He just started to find contacts from other sources.
Finally the solutions was: Linkedin
He contacted many professional and finally he found good writer which suits his niche. So he was not wasting his valuable times and other processing fees. He have a 2 content writers who works for him for the past 3 years and he is happy with them. So i would suggest everyone to use linkedin to find great talents for content writing, graphic design, video editing etc.