To buy the car new is $43,500.00 however, if you wait 18 months, it’s 55% cheaper. How much can you get the car for in 18 months? If sales tax is 7%, what will be the total cost? 6.) The extra data costs are $20.99 monthly bTo buy the car new is $43,500.00 however, if you wait 18 months, it’s 55% cheaper. How much can you get the car for in 18 months? If sales tax is 7%, what will be the total cost?