Can a non-car-owner buy auto insurance to drive any car (rental or friend's)? How does one obtain it?


The type of policy you are looking for is called a "Named Operator Only" policy, they can be more expensive to purchase but it will allow you to rent a car, now this type of policy is for liability only, you would still need to get the damage waiver from the rental company if you rented. When you are given permission to drive another person's car their insurance should cover the vehicle in the event of any liability mishap while you are driving.