1) a good slow cooker, if you don't have one. Crockpot recipes are you best chance at making good meals without much spare time.
2) Thick curtains for your room. You will improve the quality of your nightfloat sleep significantly if you can go to sleep in the dark.
3) A Keurig if you're a coffee person. Fast coffee in the morning can significantly improve the day. Alternatively, if you're more budget minded, caffeine pills are a great way to get 100 mg fast.
4) A pharmacy. Go to the pharm section of Target with at least $100 and get one of everything. Dayquil for colds, Tylenol/ibuprofen for headaches, simethicone for gas, tums for heart burn, probiotics/pepto for diarrheal illnesses, and a good icepack for muscle strains. I was always amazed how many Interns ended up doing without basic medications because they wouldn't by them in advance and were too tired/miserable/short of time to buy them when they actually got sick.
5) Good shoes for scrubs. Clogs or new sneakers. Odds are a lot of your rotations will involve a lot of walking.
6) A 100 pack of cheap pens. They disappear quickly.