How about other opinions about this? I think there are plenty of newbie ( like me ) here find it useful?
Just so that it is clear, PR value of a web page is but one factor that determines positioning in SERPs for a keyphrase search. A PR2 web page geared towards ranking highly for a keyphrase can frequently beat a PR 6 trying to do the same thing. PR value, although an important indicator, does not in itself determine SERP positioning.
Your advice is mostly directly to the "newbie" of SEO, thus I feel compelled to comment.
Renting a link from a high PR web page for the purposes of artificially inflating another web site's importance is commonly refered to as "link brokering".
Although link brokering can often be an effective PR boosting strategy, it is not, in any respect, SEO. As a matter of fact, link brokering is now being considered as a spam technique and Google has it's sights set to alleviate it's effectiveness. Both the broker and the renter will increasingly become subject to ranking penalties.
Now, the main problem with link brokering. Search engines want to provide the best web pages that satisfy a keyphrase search. Web pages that rank highly for a keyphrase search but are of little value to the searcher, and certainly not the best page for that search, flood the SERPs. This process is part of the increasing problem of seeing sub-standard web pages rank highly in comparison to better ones. Link brokering can be used as a sort of ranking scheme that needs to be carefully monitored by the search engines.
In the last four or five months, many of these ranking schemes have been dissassembled and their positioning in the SERPs have been drastically affected negatively. This is a trend that will undoubtedly continue.
So, my opinion on this matter is clear : play this type of PR boosting game at your own risk. Think of SEO as a long term, sustainable pursuit whereas a web site's contents are of most importance.