Congratulations on getting into school! I do not recommend studying before school starts because you never know what your school is going to have you learn and there is plenty of studying to do after school starts. If you absolutely can't hold back, I think the only things worth learning are your basic medication calculations, conversion amounts from metric to standard (like there are 30 ml in 1 oz), and your basic lab values for Hgb, HCT, PLT, Na, K, Glu, Ca, pH, pCO2, pO2, and HCO3.
I think the best place to spend your time is organizing your life and getting ready for being really busy. Clean out your room/apt and get everything organized. Set up a comfortable place to study with ample desk space to lay out all of your books. Read allnurses cuz there are tons and tons of threads on how to study and how to take exams. Also find time to hang out with your friends and have some fun. It may be your last chance for a while, lol.
I would not recommend buying any supplies until you hear from your school. My school had us buy a supply bag that provided everything we needed at a discounted price. We also got stethoscopes.
Good luck and I hope you enjoy school as much as I did. It's the best feeling in the world to be able to call yourself a nurse