Now that you have chosen your vehicle you will need to determine how much you will be paying per month for your car payment. You find a bank that will lend you the money for 6.2% compounded quarterly, or 7.8% compounded annually. You will determine the monthly cost and total cost using both scenarios. You will be able to change the amount of your monthly payment based on the length of your loan. So using the price for your car, determine the amount of your monthly payment based on the length of the loan, the total amount that you will pay for the car and the total amount of interest that you will have to pay. Original cost of the car The amount of your monthly car payment over 48 months The amount of your monthly car payment over 60 months The amount of your monthly car payment over 72 months. Total amount you will eventually pay for your car Total amount of interest you will pay on your loan Car payments with a 6.2% compounded quarterly. Car payments with 7.8% compounded annually.