Financial aid is designed to supplement the amount you and your family contribute for educational expenses.  You will encounter 4 basic types of financial aid: GRANTS, SCHOLARSHIPS, WORK STUDY and LOANS
Grants are typically awarded based on need and you do not have to repay them.
Scholarships are usually awarded on special ability, academic achievement, religious affiliation, ethnic background, special interest or random drawing.  You do not repay scholarships either.
Work Study is a federal program offering part time jobs both on and off campus.  You do not repay work-study funds either.
Education Loans are funds borrowed from a financial institution or the federal government.  You must repay education loans, so make sure you investigate all other alternatives before applying.