Whats the acceptable price range for an average article that is averagely SEOed?

I hire writer to write 400 - 500 full SEO article for about $5 - $7

Regards
Angga Rakasa

With the possible exception of the articles' titles, I think you probably shouldn't, Ethan.

For many reasons, your articles are likely to prove far more profitable to your business if you write them without SEO content/considerations being taken into account by their authors.

You don't need "SEO content" for your traffic to find the articles: you just need to have them published where your potential traffic is already looking (and that isn't in article directories or on "Web 2.0" sites).

The important things to know (about articles, in this context) are ...

(i) Publishing articles just on your own site isn't really a traffic-generation plan at all: all that can ever bring you is some gradual, eventual search-engine traffic that's typically very low-performing, unresponsive and poor quality anyway, and in the overall scheme of things "generally not worth talking about". And perhaps especially in your niche. Using articles for marketing is about taking your content to the places where the targeted traffic you want to attract is already looking/reading/visiting (after publishing it first yourself, to secure the initial indexation-rights, of course);

(ii) Article marketing isn't about how many articles you have: it's about who reads them (relates to the point above, and to other considerations);

(iii) "Good content" is content that publishers in your niche, who already have access to the traffic you want to attract, want and choose to share with their own subscribers, readers and visitors (either by publishing it or linking to it). That's a very simple, practical definition of "good content", but I think it's a useful one because it relates directly to how content produces income. Or, to word it the other way round (same thing, really), content that directly produces income is content that publishers in your niche, who already have access to the traffic you want to attract, want and choose to share with their own subscribers, readers and visitors.

Unless the topic of your site is SEO, you don't need any SEO content. Focus on content that will inspire human readers to take the action you want them to take. If you choose to syndicate content, that Most Wanted Response is a click to your own website.

If all you want is average content to fill up your site, you can find writers who don't yet realize their worth and get average articles in the $5 range. I'll warn you, expect to cull through some duds and fakers at this price point. And, after the dust settles, you'll still just end up with an average site, with nothing to distinguish it from a million others.