[Alupis]

You may not even need additional insurance. Some insurance providers cover accidents caused by you, no matter the car you're driving - so long as it's not your permanent car.

For example, you borrow your friends truck and wreck it, etc.

[Schweigi]

This might not be enough. Rental car companies charge not only the damage done but also any revenue lost on the car while in service. Usually the credit card rental insurance will cover this gap.