Amazon offers Prime members the MOTOsafety GPS Tracker & Driving Coach, model no. MPVAS1, for $15.85 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping adds $5.01.) That's the lowest total price we could find by $57. It monitors location, direction, speed, traffic, and more using Google Maps. (There's also a tracking service, which costs $19.99 per month.)