I have seen lots of links for sale on sites with a high PR, however I was wondering is it worth paying a lot for a high PR link for a new site since the search engines must surely know this is probably a paid-for link? Has anyone bought links from sites with much higher PR than their own and got a quick increase in their own rank? Else would it be better to go in stages like get some cheap PR3s first, then PR5s before trying to get some links from PR6,7,8 sites? Is there a maximum jump anyone would suggest before red flags start waving?