Have students determine what percentage of their income/month they spend on clothing, recreation, transportation and other.
Have students research the internet and come up with some budgeting guidelines for the average family. They need to include all possible expenses. Develop and hand in a budget guideline that could be used by an average family. (This could be extended to have them develop a program to do the calculations for their budget)
Use the budget that the students developed or a pre-designed budget. Present them with various family scenarios and an assigned monthly income. Have them develop the budget for this family. They can work individually or in a group. Present the budgets to the class and allow for discussion. They must be able to defend their budget or change the budget if they can't defend it.
Give the students filled out budgets for various family scenarios and fixed monthly incomes. Give them unexpected expenses for each of the scenarios and have them adjust the budgets to reflect these changes.
Have students do a written assignment.