I just attended an admitted students day at USC for the MPA program and this is what they told us about federal loans which I believe is true across the board and not just at USC.
Just for filling out the FAFSA you are eligible for the Federal Stafford Loan Program. Each year you are eligible for:
$8,500 Subsidized loan (no interest accrual while you are at least at half-time student, and for 6 months following graduation)
$12,000 Unsubsidized loan
The interest rate is 6.8%, and there is a 1% fee upon origination.
Assuming you have no defaults on your credit record, you are also eligible for the Federal Graduate PLUS Loan. This loan has a 7.9% fixed interest rate with a 3-4% origination fee. They do not look at your credit score for this, just that you don't have any defaults or problems making payments.
You can borrow up to the cost of attendance (tuition, fees, rent, cost of living expenses, etc) as determined by each school individually based on specific factors of the school. If you receive any merit-aid this is deducted from the amount you can borrow.
Let's say that your cost of attendance for a year is $50,000 and you receive $10,000 in scholarship. You can then borrow the $20,500 (8,500+12,000) in Stafford Loans and $19,500 in PLUS loans.
Again, as I said, this is what we were told by the USC financial aid office and from my research it seems to be true across the board, but certainly check with your schools financial aid office to verify.
Good luck out there!