Some questions about money matters which I think are quite important:
- How much is the net stipend, after deduction of all taxes? And what part of those deductions do you get in tax return?
- What sort of health insurance do you get? What is the usual co-pay for prescription drugs and doctor visits?
- If there are any semester fees to pay, do you need to pay them out of your stipend? And do these fees cover monthly bus passes? If not, how much does the transportation cost?
Another unrelated question:
- If there is a particular professor you'd like to work with, how friendly/supportive/pleasant is s/he known to be? (I would also ask my current adviser about this)