Well probably not PR9 cuz there aren't very many PR9 sites on the net and the people who have them aren't selling links. So I'm talking legit PR, with the link coming from a page that has that PR. The scale seems to be exponential, with PR0 links going for between $1-5 per month and I think I've seen PR8 for $1,000 per month. Once again, I'm talking about legit PR, with corresponding high domain authority and page authority. I'm not talking about deep pages with no PR and I'm not talking about someone creating a wordpress subdomain for you and trying to pass that off as a PR9 link because wordpress.com happens to be PR9. I'm also not talking about pages with high PR but no backlinks and no authority. I feel the need to specify so people aren't like "BUT TURDFACE, I SAW A PLACE TO GET PR9 LINKS FOR $5." No you didn't. On average, what are you paying, or what is fair market value?