What are these people concerned about?

M: Did you see the list of books for this course?
W: Yes, Dr. Downs said he expects us to get the first five on the list. He is going to discuss them in detail.
M: Arc you going to buy them?
W: I don’t know. These books are expensive. And I don’t have a lot of money on me.
M: How about sharing them with me?
W: Sounds good.
M: Let’s do this. I will buy three and you buy two of them.
W: I would rather do it this way: we pay fifty-fifty for the books now. And at the end of the course you can take the books you find more interesting and I will take the ones I like.
M: What if we both like the same books?
W: Come on, we are not going to argue over that. Are we?
M: I was just joking. It’s definitely a better idea.
W: Then let’s get the books as soon as possible.