RelayRides, based in Boston and now in San Francisco, allows car owners to rent out their own vehicles by the hour. The owners set their own rates, starting at $6 an hour (once again, less than Zipcar) and get 65 percent of their take, with 15 percent going to RelayRides and 20 percent going to insurance. The service provides insurance (up to $1 million) and a screening process as well as the technology to track the cars' use, but it mainly serves as a way to connect people to people. It's a step in between Craigslist and a company like Zipcar.