Check Cooling-off Rule in your state.....

In CA, if you buy a USED car from a dealer with the price less than 40,000, you may get a 2-day sales contract cancellation option. But you will have to pay a fee based on the sales price. That Cooling-off Rule does not apply to new cars.
If I were you, I would check with the DMV of your state to see if there is cooling-off period for new cars.