PR is a big part of price, but in the end if you have the hits and other high rankings you can still get some good money!
I personally have a
PR of 0 lol, due to only getting 200 a day my links are valued from $3 to $5 a month, but no one would ever buy a link from my site, its full of IT nerds who love to read up on my pain lol.
So unless you have a good techy site and want a link from me then theres no point