Relay Rides is a peer-to-peer carsharing marketplace. Car owners can rent out their vehicles to people and set their own prices. They can just list their car, upload some photos, and update a calendar. The company notifies you if someone wants your car, but the owner has complete control, and it even has its own insurance. Relay Rides also offers service at airports now — in select cities, you can just leave your car there. And if you are the one needing a car, it’s often much cheaper than renting from Enterprise or Zipcar, for example.