If you look at HMS on the MSAR, you'll notice that it has a lower average graduation debt than almost ANY school, yes that's including state schools that only accept in-state residents. The financial aid schools like Harvard give to their students is typically nothing short of amazing. Even though the "sticker tag" says that it is expensive, in reality, a Harvard Med education will probably at least match the price of a state school, if not better it.
Other schools that have <$100k graduate indebtedness: Hopkins, Mayo, MCG, Stanford, and I'm too lazy to keep flipping through the book.
Boston and Tufts, on the other hand, have among the highest graduate indebtedness
Stupid Boston cost of living.