I recommend hitting allheart.com and getting their cheapest white coat and also their store-brand "Cardiology" stethoscope. That stethoscope runs about $25, is actually perfectly adequate, and will make a great backup scope for when you, your friend, or your resident forgets or loses theirs. It will work well for long enough to give you plenty of time to try out others' stethoscopes and decide what works best for you.
A backup white coat is good to have too.
I think I bought my Cardio III on allheart.com and my Welch-Allyn portable diagnostic kit on eBay (~$180 IIRC).