I have heard a lot of conflicting information about the books, some people sayings we need them, most others saying we don't and the book list says they are all required... Can you give us some insight?
Honestly, it depends on the strength of your academic background and what style of studying you use. Some students never crack open their books while others find them a necessary resource.
I am a "better safe than sorry" kind of gal. I'd rather have all of the books on hand, even if I never use them, just in case. I find the best price on the books, so I'm not out that much money, and then resell the books to the new incoming class to buy my next batch of books. I usually find the best prices at Half.com, but sometimes Amazon has a surprising deal. Shop around. Also, you can split the cost and ownership of the books between yourself and a roommate or friend in your class to save money.
If you are absolutely bound and determined not to buy all of the books, I would definitely recommend that you at least have access to the book for Biochemistry. That class heavily depends on material from the Clinical Correlates and the Chapter Questions from the book in addition to the lectures.
Also, IPHC has regular quizzes that may include questions about the readings from "Introduction to Healthcare Delivery: A Primer for Pharmacists." The Medical Microbiology class has assigned readings that are covered on the test, but not everyone did the reading assignments. Every once in a great while, there are readings for the Dosage Forms class in "Ansel's Pharmaceutical Dosage Forms and Drug Delivery Systems."
In addition, if you are weak in a particular subject area, be sure to buy the corresponding book (e.g. Anatomy and Physiology, buy the Pathophysiology book; Chemistry, buy the Medicinal Chemistry book; Microbiology, buy the Medical Microbiology book, etc.)
Finally, be aware that the courses are modified and updated each year, so their requirements may change and my advice may no longer be accurate to your needs.
I know this was a long winded answer but it all boils down to, "do whatever you are comfortable with." I hope this helps! Best of luck!