The Dialogues of Plato (5 vols.) has passed the mark at $12, but the bidding doesn't close till noon March 1. It's pretty close to $10, but with the time left, I think we can get it down to $6 (definitely $8).
http://www.logos.com/product/29766/the-dialogues-of-plato
Also, it would be nice to get The Works of Aristotle (12 vols.) down to a lower price before it crosses the line (it's currently the highest at $50).
http://www.logos.com/product/29737/the-works-of-aristotle