Start with a discussion about money the last year of high school. Make sure your college student knows what you are paying for and what she's expected to cover. This way the student can save enough from a summer job or plan to work while in school.
Do some research, and have your child do the same. Have him find out how much students spend on entertainment, books and other items. He can ask the admissions office or someone else already attending the school.
Make a spreadsheet together. There are several examples online, or you can design your own. It's the same kind of thing you do for yourself: income and expenses on a monthly basis.
Tell your student to explain how expenses are covered. Ask lots of questions. For instance, if the summer job brought in $3,000 and monthly expenses are more than that amount, ask how she covers the shortfall or where she needs to make cutbacks.
Suggest you dole out money on a bi-weekly or monthly basis for a while. Some students hand over summer savings to their parents and get periodical chunks sent through Internet banking. Not only does this help them budget, it keeps them away from impulse spending.
Teach a student about credit cards. A credit card with a small spending limit, which you insist she pays off every month, not only helps the student get a credit rating for later but teaches about the trap of living outside your means.