As long as your parents have current insurance coverage on their car then there's no need for you to have additional insurance coverage to drive their car.
Just like you can drive a friends car without your own insurance as long as they have insurance in their name on the car you're driving.
You cannot get insurance on the car yourself if you do not own it so your parents would be the ones to have car insurance on the car they own.
You can freely drive your parents car with their insurance coverage as long as they give you permission to drive the car.
I have driven my parents extra car back and forth to work when I first started driving while I saved up money to buy my own car.
I always just drove the car with their own insurance coverage and didn't require any additional insurance on the car.