Many people who are new to the world of SEO seem to be unclear about how link juice works. They think that the inner pages of any website do not provide you with any link juice, even if you get a link from them. For this reason, they are almost always ready to pay top dollar for getting their links on high PR pages!
As far as the SEO thoery goes, Page Rank (and therefore link juice) is distributed all over the website in question. So for example, if you have a website with a PR of 6, the inner page on the website (which might have PR 0) will still send you considerable link juice when you put a link there.
But then people ask: What is the use of the Page Rank if it does not accurately describe how much link juice a page will send out.
First of all, Page Rank is an inaccurate measure. It only roughly tells you the importance of a page. Secondly, link juice flows throughout the website, so you do not really need to check the PR of a page to determine how important it is.
Instead, just check if the website as a whole has a high PR. If it does, you can get link juice from placing a link on the inner page. But remember, the link must be DoFollow. A lot of websites are now shifting towards the NoFollow attribute, because of all the widespread spam out there.
Although I can convince people in many cases that inner pages pass link juice, I normally use this reason: I have made websites rank high, not by putting links on high PR pages, but on the inner pages of high PR websites.
The target websites would not have ranked higher in Google if the inner pages of source websites did not send considerable link juice to the target website.
I hope that clears out a lot of misconceptions out there!