It does work, not best way to get money, but it's easy way to monetize some old projects that has PR but doesn't have significant traffic anymore.
Babganoosh, who cares if they buy
Anyway, they more search for relevant links. PR only offers some view on quantity and "might be quality: of links.
"Might be quality" is often small, cause plenty of links that produced PR aren't relevant
I'm telling to sell, not to buy xD