The rental rate as listed by the individual car rental agencies is the base rate for the length of the rental. As you proceed through the reservation process, insurance and other options will become available, allowing you to know the total price before you make a reservation. Insurance Policies vary by agency. Once you have selected a vehicle, you can check these at the Policies & Insurance tab of the rental center.
Most agencies require proof of existing Insurance to allow any insurance waivers. Again, do check the individual agency policies at the Policies & Insurance tab of the rental center.