Onstar is a safety and security system built into many new GM models. The service plan that accompanies this system features in-vehicle assistance from a live agent. The system automatically senses when you've been in an accident and notifies emergency response teams. It also can give you directions, some cars can download the directions to their GPS.

If you buy a new car that is Onstar enabled, it comes with a 1 year subscription. To activate or renew your Onstar service, go get in your car and drive nowhere. Instead, do this:

Push your blue OnStar button
Note: Your vehicle may be inactive and it may take an extended period to connect with OnStar the first time you push the blue OnStar button.
When prompted, say “Advisor”
Be sure to mention the Three Months On Us Trial*
Your OnStar system will be active immediately, once the call is done

You can cancel your service by pressing the blue "Onstar" button in your car and notifying the agent you would like to cancel. If you have a paid subscription, you will be refunded any full unused service months remaining.