Graduate school can be an investment in your future. It costs money and you may have to borrow, but the odds are pretty good that you'll still come out ahead financially (not to mention other factors like having more choice).
It's hard to get through school without loans, but you can minimize the debt you'll have to repay.
Research the type of degree you're getting and the best way to fund it. For example, MBA students don't get as much in grants as students in other fields, but their employers are more likely to help pay. If you have to borrow, start with federal loans and only use private loans after you've exhausted your federal options.
If you can match your funding strategy to your field of study, you can keep debt levels reasonable. The Wall Street Journal's Rachel Ensign covers paying for grad school in more detail.
Further reading: