First, this is an AMAZING resource from Search Engine Land. Smart content writers do WAY more than putting words on a page.
Other things to consider are: Do you find their writing engaging? How does their writing position?
What “level” of freelancer do you need – someone who is newer to the game? Years of experience, so they can help you with other things besides the writing? Do they have industry expertise?
Here’s a big one. Does the writer “get” your brand and your company? That “click” is so important.
As with other things, you get what you pay for. You don’t have to pay top $$ for every piece of content, but good writing costs money. Paying $50 for 1,500 words probably isn’t going to get you the best content. Sales content can be $$$, too.