Thinking about buying a new car, RV, boat, ice house or other vehicle? Try our easy loan calculator to estimate how much you may be able to spend! Your monthly payment is based on the net purchase price, loan term and interest rate for the loan. The loan amount is based on the net purchase price of the vehicle, boat or ice house (plus sales tax) or the price less any cash rebate, trade-in or down payment. If you have an outstanding balance on a trade-in, that amount is added to the price of the item you are purchasing.