I think going on your parents' plan is the way to go. My cars are in my name but insured under my mom's and its $140 a month total. I have liability only on the bimmer and full coverage on the Mercedes. It originally was $160 when I first got my license but it went down $20 right before my 18th b-day.
I don't even want to think about what it would be if the policy was in my name.