When purchasing relevant links, does the entire site have to be relevant or just the page the link goes on? Suppose I buy a link on a page which is relevant to my site but the overall site has no relevance would it make a difference?
Well depending on which sites you have but overall getting links on sites with pagerank doesn't hurt at all. Actually it could definately help.
I would think that as long as the page your link is on is relevant that would work. For instance, I have a photo hosting site. If I exchange links with an electronics site and have my link put on a page with digital cameras/photography, I think that would be viewed as relevant even though technically electronics is not as relevant. Is that what you mean? Can you give an example? Basically, nobody really knows what se's view as relevant. In general, if the page your link is on would benefit your site visitors, I would say go for it. And, if this link is on a high pr site and also helps bring your targetted traffic, that is even better. Believe it or not, sometimes we have to actually think about our visitors and not be so obsessed with the search engines. Hope this helps.