 The national bank could print money and use that to buy the car, but these days financial transactions are carried out electronically so there is no need to actually print the money. Instead a number on the national banks computer system is added to. It's just another way of printing money but electronically. Of course the more money you print the less it becomes worth. Look what happened in Zimbabwe, printing millions of billion dollar notes didn't mean everyone was rich it just mean that a billion dollars could buy you less i.e. inflation occurred by deflating or diluting the value of money.