So you are looking for a tool to log your mileage effortlessly? The Mileage Ace GPS Mileage Tracker can help. It comes with accurate GPS signal, WiFi, and enough memory to hold years of driving. Mileage Ace turns on/off with your car. It tracks date/time, addresses, distance, driven path, trip duration, and other relevant data points.
The unit has a business button to log only business trips quickly. Available for under $400 at this time. You can find out more about it here.