Plug the numbers into last years copy of TurboTax and you will have a good idea of what it will cost.
Back to the 7,500 insightman's idea will help someone who doesn't have a 7,500 tax liability for 2020 and does have an IRA put the 7,500 to use since it is use or lose. eBay has prior year versions of TurboTax pretty cheap if you need to plan. The key is the car has to be put in use in 2020 in order to use the credit for 2020.
If you get the car in 2021 and owe taxes for 2020, estimate what your 2021 liability will be after the credit, and adjust your withholding down, then pay the difference to Uncle Sam.