Rental Car Insurance Coverage Tips That Save Money! Most people don't know what insurance to buy or what insurance to decline. So they either buy what they don't need or decline what they do need. Either way, people renting a car could be risking their financial futures over a few dollars. This book clears the air about which coverages you should buy when renting a car. You might find that you don't need ANY of the car rental company's coverage at all. But READ THE BOOK!!