Can K2 be used to set up an Amazon type review system?

A product listing with comments containing individual star ratings?

I was thinking something along the lines of Mosets Tree. However Mosets Tree is too expensive for what I am looking to do. I looking to add book reviews to a classroom website, no profit involved. Anybody know of a free extension that will do this? I don't mind donating a few dollars to the developers, I understand the time required.