GP might be paying only third-party insurance. I'm not sure about America, but at least in Australia, AU$500 (US$400) per year will get you third-party insurance if you're under 25, and if you're driving a beater car you don't need any other insurance.

I looked at getting comprehensive insurance on my old car, but in the end the excess was greater than the value of the car. I wouldn't be surprised if it was the same for GP.