I agree with Doc.
Take a look at this loan payback calculator: FinAid | Calculators | Loan Calculator
For $90,000 @ 6.8% and 10 year payback your monthly payments will be $1,036 (after taxes).
So you will need to make this much gross to pay for it:
* .66 = income after taxes (about 1/3 of your gross)
* .5 = income after housing (about 1/3 of your gross)
Disposable income (about 1/3 of your gross)
out of disposable income you pay for stuff like cell phone, food, entertainment, internet/TV, car loans.
So if you assume that you can pay back this loan with 1/3 of the remaining because you have all those other bills to pay then the max you can finance would be 1/9 of your gross income.
Expressed another way would be 9 * the loan amount.
Then multiply by 12 since this is a monthly number
So you would need to gross $108,000 a year to cover the cost of this education.
Think you can do it by cutting back? How many years do you think you could do that? And it'll never happen if you plan (or don't plan) to have a family.
This from a guy with a 25 year old finance degree from a state college.