I came across that book in a random search. It says I can buy the book for $17.99 or rent it for $6.19. The button you click to rent it has a "Details" help button that shows the rental options -- 30 days, 60 days, etc.
Is this something new? I suppose it might be limited to big publishers but I have never seen it before and I spend a lot of time wandering around the amazon website. I clicked on several of the current bestsellers and none of them are for rent.
I believe this is considered a textbook of sorts. Renting a textbook for a college course is certainly cheaper, and for college students, cheaper is better. I vaguely remember reading somewhere about the possibility of renting digital textbooks.
Many thanks to both starnssv and extradimensions. I guess I've just never stumbled across a textbook before. And I don't remember textbooks having such fun-sounding names. Somehow I missed all the classes on Film Noir. Anyway, I think it's great that students are able to save some money by renting a textbook.