You need to keep the insurance group as low as possible.
Use the left hand panel to find the insurance group of any particular model or (perhaps more relevant to you here) use the right hand panel to obtain lists of models by groups:
http://www.parkers.co...car-insurance-groups/
A couple of hints when seeking insurance:
1. The most basic insurance isn't always the cheapest. Don't just go for 'Third party' (or 'Third party, fire & theft') policies. Check the prices of 'fully comp' policies as well. They can sometimes be cheaper! ;
2. Look at adding a more experienced driver to the policy as an 'additional driver'. It's perfectly legal (even if the additional driver never actually drives the car) as long as the policy is in the teenager's name. Adding an additional driver can significantly reduce the cost of a policy.
Chris