Selling low PR blog roll space?

If you want to increase your motivation through SEO, one way to do that is to occupy some blog roll links on a high PR page. If you want to do that, then a deal should be made. In DigitalPoint forums, there's a section called Link Sales, which more people are relying on selling and purchasing blog roll links and one-way permanent backlinks to high PR and traffic sites. It's a good thing in which you have to deal with them for good. Most of them are successful in their link sales deal whether on buy or sell.

But what if you sell low PR blog roll space, is it worth for their money? For me, I think not because most of them are targeting huge UV's daily and PR as well. The more backlinks you have, the higher your PR soon increase and also your revenue in Google Adsense and Clickbank.