The National Association of Attorneys General has noted that "the actual cost of renting a car may exceed the advertised rate by as much as 75%" because "advertised car rental rates in print, broadcast, and Internet advertising may not fully or clearly and conspicuously disclose the fees, taxes, and surcharges." So, before making a rental car reservation at that great sounding daily or weekly rate, ask to know all of the charges, including sales taxes, airport taxes, mandatory insurance policies, miscellaneous facility fees, and the loss damage waiver (sometimes called the collision damage waiver).
If you agree to pay the loss damage waiver fee, the rental car company waives its right to recover money from you for damage to the car from a collision or for theft of the car. The waiver does not affect your liability for damage to other vehicles or property.
If your auto insurance covers you for damage to a rental vehicle you will not need to purchase the loss damage waiver. Likewise, some credit cards offer coverage for damage to a rental car if you charge the rental to the card. Therefore, before you book your next trip, consult your automobile insurance and credit card policies regarding what coverage you have. And remember to ask about all of the "additional" charges for the rental car.
Be sure to read the rental contract carefully before signing. Verbal or oral promises by the rental company representative are not enforceable. Make them put it in writing in the contract.