I lived off financial aid with no job for most of my first year of graduate school (then supplemented with savings and a part time campus job which was small pay and very few hours). It worked out great because I was able to totally focus on my courseload and adjust to being in my own apartment in a new city for the first time.
Ultimately, it depends on how much aid you recieve and how well you're able to budget your expenses. Have a plan and stick to it. When you're offered credit, take it, but then use it sparingly.
Best of luck.
p.s. I had loans to pay back beginning 6 months after I graduated. I had it all paid off in a years time by "living simple" my first year as a professional librarian. The increase in pay and job satisfaction made the investment of time and money very much worthwhile.
