Nexar's dashcam app is free, but at the cost of your data

We likely aren't going to get flying cars anytime soon, but we will have self-driving ones. They'll be packed to the gills with sensors to keep us safe and sound as we Snapchat ourselves cruising down the highway, bellowing along to our favorite Urfaust tracks. But those are a ways off, and the phone in your pocket already has a pretty solid set of sensors in it. Plus, using a device you already own is far more economical than buying a new car. A $7 mount holds a phone, while the free app uses your gizmo's onboard accelerometer, cameras and microphone do the rest of the work.