National, Thrifty, Avis, Enterprise(?) and Alamo rent to under 25. Funny thing is, I paid more for the four hour car rental than the four hour flight!!!
It's not because of 'insurance' that they charge you $80 to drive a cheap Chevy, it's to make more money. You could have your own special insurance, or your credit card could cover all damage to the car as long as you pay with it, and they will agree with you but still want $80.