How should I know whether or not to buy or rent my books?

I am going to be starting my introduction to nursing course at polk state college and I hope to apply for the program in fall but the nursing books are not cheap and I was wanting some advice to what books i would need to buy versus renting. I have a list of compared prices from different websites and from the schools website, but I do not really want to buy a book if I won't need it later on.
I would appreciate any advice
thank you