When you are going to buy links, you need to make a smart choice. So I would advice you to choose links which bring you more PR-weight per $1 inside a certain PR. Let me explain this a little bit more. For instance, you see 3 links with PR3: Link X provides 148 PR-weight for $7 Link Y provides 130 PR-weight for $6 Link Z provides 57 PR-weight for $3 This means that each link gives your webpage the following PR-weight per $1: Link X = 21.1 Link Y = 21.7 Link Z = 19 So at first glance it may seem that Link X brings more PR-weight, Link Z is less expensive, and they are good choice. But when you compare them, you can notice that Link Y brings more PR-weight per $1 comparing to other links, so this link is the best choice in your situation. At the same time you must remember that you should compare links only inside one PageRank because otherwise you might end up buying only links with high PR, and this doesn?t look natural.