Calculating cost basis of new car for depreciation

I purchased a new car in 2021, and I'd like to know how to calculate dollar amount as cost basis. For example, the car was $50k exactly total price on the purchase contract. There was a mfr rebate of $5000 for conditioned on using the mfr's lender, a clean fuel rebate of $1000 from the state, and another misc rebate for $500 from a third party. The amount financed, not including any add'l down payment was $43,500. Post purchase, an add'l rebate of $5000 from the state was given due the fact that the vehicle was an EV. What is the actual cost basis for depreciation?

 

Second question: When taking depreciation, whether 1st yr or subsequent years, and whether 179/bonus in first year or straight line, does one take the depreciation only, or the depreciation in addition to actual costs for the first and subsequent years?

Thanks