The length you are required to keep your device installed; The year, make and model of the vehicle you are installing your ignition interlock device in; The state you are installing your interlock device in; The features you are required to have (GPS, camera, real-time reporting) In addition, installation costs usually average between $60-$80. At Intoxalock, we know that expenses are a major concern in the aftermath of a Driving Under the Influence (DUI) offense. An ignition interlock device should be a means of keeping you safe on the road, maintaining your everyday life, and expediting your DUI legal process. It should never feel like a roadblock standing between you and getting back your normal life.