Well currently, I'm thinking to purchase blog posts at several niche blogs. And i'll implement the direct sale link into the blog post. I mean, i'll advertise on blogs which are about shopping, and in the blog post, i'll put the link with further creative information about the product. Do you guys think that this will make me some revenue or should i go with blog posts to just increase my website's PageRank?
It will be beneficial for sure. The problem with contextual links like that is that you only really get the 'visitor value' when the story is new. After a day or so it gets lost in the shuffle and you lose all the traffic. On the plus side though, the link will always be there so that naturally helps your PR. Hope this helps