The PR is nice to have,, But It's about the name, A good name will sell even without Good PR.. Try to sell this, It's PR 9 (wink) buybrokendamagedgolfballs.info
There are more factors: 1. does the domain gets any traffic? 2. length of the domain name 3. extension (com,net..) etc.
How much "abced.co.cc"(it's not real name) with PR4 is worth? Now it has 7-10 visitors/day, but in case with this domain it depends only from website content and promotion qality. Profit to date - $6.3 per month.