While rental car insurance rates work out cheaper than normal insurance on a lump sum basis, they are more expensive on a “per day” basis. Your normal insurance is usually paid monthly or annually, while rental car insurance is paid daily or weekly depending on how long you are renting the car for. The average price of insurance on a rental car is between $10 and $20 per day, while the average cost of normal car insurance in America last year was $1,844 for the year. This averages out as $5 per day. Therefore, it is 50% to 75% more expensive to take out car rental insurance than normal insurance.