What you paid for the car is the price listed on the sales reciept no matter how the sales price was eventually paid. You could have paid by cash, a check, a Credit Card OR funds you got from a loan (or any combination of payment types) and the answer is still the same ... you paid X for the car period. Now if you take out a loan then the interest you pay on the loan is an expense ... it is not added to the cost basis of the car.
