The best credit cards to use for rental car insurance. Should you tick the box for rental car insurance at the Avis, Budget or other rental car counter? Or does your personal auto insurance or credit card already offer this benefit? Given that supplemental insurance for rental cars can cost around $15 to $30 per day or more, it's worth asking these questions first.Figuring out card benefits before you travel is smart. But it can be arduous and confusing to wade through the perks offered by multi