Can someone tell me the value in $$ of a permanent PR6 Dofollow link with zero outbound links. Thanks.
it depends on how many links on the page ... zero outbound links with 60 internal links would not be worth so much. zero OTHER outbound links (apart from the one sold) and Zero internal links would be worth quite a bit.... as long as you are talking PAGE PR not site PR.
The main factor for this would relevance. A PR6 link on a site not related to yours will not be worth much compare to a PR6 link on a site in the same niche as you. The authority factor will be the main benefit.
It is very beneficial if it links to your content in the middle of content, and the page is not spammy, and it is an authoritative site (which it should be if the page is PR6). Go get more links to build up your backlink profile and you will be ranking well.