There are literally a ton of websites out there selling text links. From newspapers to newsless papers. Here are a couple of the networks which aim to undermine the ability of search engines to rank websites based primarily on link popularity.

http://www.pradnetwork.com - network with a 50% payout and links starting as cheap as $29.00 a month for PR4

http://www.linkadage.com - online link auction

I see the appeals these networks have. If I could get $15/page per month X multiple thousands of pages I control...I would be making a ton of money.

There are more elequent ways to buy links than blind auctions or blind sales. Given these prices some directories are exceptionally appealing!