But you can get in on the car-sharing action yourself from the other side of the equation, and use your idle vehicle to earn some extra cash.
RelayRides, launched two years ago in Boston, allows car owners to rent their cars and earn money in nearly 1,000 cities. So while you're at work, at a movie, or out of town, your car can make money to offset the cost of car insurance, gas, and car payments instead of sitting in a garage.
How It Works
RelayRides matches car owners with potential car renters and provides insurance that protects both parties in case of an accident.
Shelby Clark, founder and chief community officer of RelayRides, says the average car owner on RelayRides earns $250 per month. Some top earners make $1,000 per month. RelayRides keeps 40% of the fees charged by owners to pay for insurance on all vehicles.
You, as a car owner, control much of the process -- from setting the rental price (RelayRides provides guidance based on car and location) to controlling the schedule to whether or not you're willing to provide pickup service to potential renters -- and can rent your car as often or as rarely as you want. (The company's top earner does airport pickups for renters in Los Angeles, Clark says.)
Don't Ride With Strangers
In order to use a car, a renter must create a profile on the RelayRides site. Renters and owners are encouraged to write a review of their experience. So before you hand over the keys, check out what other car owners say about their experiences renting to a particular individual.
"We encourage everyone to create their profile using Facebook so that they can find out if they have mutual connections on Facebook," says Clark. "The idea is to make the experience more like borrowing a friend's car."
Just as with a traditional car rental, the owner and the renter should spend a few minutes examining the condition of the car to avoid disagreements later about dings or dents. Renters are required to return the car with the same amount of gas in the tank as when they take possession of it.
If you need your car back by a specific time, you also need to allow some leeway in case your renter keeps your car overtime.
While the majority of car owners coordinate a meeting place with their renters to exchange the car keys, owners can also opt for a remote access device from RelayRides that allows the car to be unlocked by text message. In July 2012, RelayRides partnered with General Motor's OnStar program to allow OnStar subscribers to rent their vehicles with RelayRides using their existing keyless entry system.
When Accidents Happen
Insurance coverage is mandatory with every RelayRides rental. "The car owners keep their own car insurance, but the moment someone rents your car and starts driving it, the car and the renter are covered by our insurance," says Clark.
"We keep complete detailed records of who has the car at every moment, so if the owner gets a red light camera ticket in the mail we'll know if it happened when a renter was driving," says Clark.
Other Ways Your Car Can Earn You Money
RelayRides isn't the only car-sharing service, nor is it the only option for earning money from your car.
With Zimride and SideCar (side.cr), you can offer to bring passengers along on trips you are already taking and earn money along the way to pay for gas. You can use JustShareIt and Getaround for car-sharing and charge hourly fees. If you have a designated parking space in some desirable location, you can rent it with Parking Panda.
Whether you opt to share your car or not, it's good to know your car can pay you back for a change instead of sucking your dollars into the gas tank.
Michele Lerner is a contributing writer to The Motley Fool.