What effect does pagerank have on a site's value?

[SEO]

I have a few sites that the pagerank has gone up on, 2 are PR3 now, but I'd like to know what value is put on different PR's. I know PR1 is less valuable than PR2, is less valuable than PR3 etc. but is there a minimum value that a website could or would sell for depending on it's pagerank? I.E a...