Young Family: A dependable vehicle that can grow with them. Gross income: $11,667 (before taxes and deductions), Take home pay: $8,892, Expenses: $7,908, Savings: $35,000. New SUV: $33,225 (sticker plus tax, title and registration. Total loan: $26,580. According to the 20/4/10 rule, young family can buy a car when they make a 20% down payment of $6,645 are financing the car for 48 months with the interest rate of $3.89% and insurance(mothly) for $52 and the monthly payment of $599 does not exceed 5.15% of the gross income after subtracting from insurance.