The first step in the discerning process is to pray, pray, and pray some more.
Are you looking to get your Masters to become a priest or a professor? Both should be taken with serious fervor but with the former step talk to your local priest often. From there he would give you suggestions as to where to go. The latter step should be done by talking with (whether you’re in high school or college) your academic supervisor and even your school’s career councilor.
Depending on the college/university you choose there should be some scholarships available and I’m sure there are some outside scholarships to help lower the debt. Fill out your FAFSA. That will definitely help you in the long run.