Rent. Groceries. Heat. Lights.

Every adult knows it all costs money. Lots of it. But your teenage children probably don’t. Or at least don’t know exactly how much, or how that cuts into your discretionary income. Many might not even know what that phrase means.

Enter the “Financial Reality Fair,’’ being held next week at Wall High School. Sponsored by First Financial Credit Union, in conjunction with the New Jersey Credit Union League Foundation.

The full-day, hands-on event is designed to teach youth the value of money and what it takes to run a household, organizers said. After identifying a career choice and starting salaries, students will be provided a budget sheet requiring them to live within their monthly salary.

“Of course, there are many temptations for additional spending and students must learn to balance their wants and needs to live on their own,” said Kathleen Zimmer, Business Development Director at First Financial.

Students learn how to finance cars, furniture, appliances, learn how to get their own cell phone plan and about buying food and will be expected to figure out how to pay for all life’s little extras, such as gym memberships or trips to the nail salon.

Financial counselors will be on hand to help students explore the importance of planning for future needs and preparing for future financial challenges through savings.

At the end, students will balance their budget sheets – their financial reality check, and talk with counselors about their fiscal choices.