A low payment can leave a large part of the price for the end. To compare financing with paying cash, add up every payment needed to keep the car.
An example with numbers
An offer asks for $4,000 down, 36 payments of $250 and $9,000 at the end. The nominal payments add up to $22,000. If the comparable cash price is $20,000, the difference is $2,000, before considering timing and other charges.
Try it with your numbers
Work out how much you would need to set aside each month to have the final payment ready. In this example it would be another $250 for 36 months, with no interest.
Example figures for learning purposes. They are not a recommendation and do not replace professional advice.