Its not all about PR guys...if the content is highly related it will do way more for your rankings than just a link on a PR4 website or whatever.
But for selling links you do need a higher PR simply because people use it as a way to put a price on the link. I'd still buy a link, if there was a post on it of like 500 words about my niche.
You could submit it to article distribution sites, so you will get points for publishing other peoples content, and in return publish your own content on other peoples websites.