Thank you for your inquiry. CarInsurance.com can not offer specific legal advice; however, based on past experiences your legal obligation would be the same. In other words, you would continue to be liable for him because of his age. The cost for the insurance would be the same regardless of who purchased it. One of the many factors that determine the price includes the drivers insured on the policy. Your son would be rated on the policy in both scenarios.You can obtain a car insurance quote here. Enter your zip code and then some basic information on the pages that follow.