If you have a vehicle that you don't use every day, you can rent it out to earn extra cash. Website services like GetAround.com and RelayRides.com offer a service that you can take advantage of to make extra money. These companies also provide a nice insurance package to protect your vehicle. Renting out personal cars is still a fairly new concept, so the service might not be available in your area yet. If you live in a major metro area, though, it's worth checking out. Here's how it works:

Sign Up for the Service

First make sure that a local rental service is available in your area. If there is more than one in your city, you can compare the services and advantages or disadvantages to each before making a decision. Once you choose the one you want to use, you can fill out a simple online form to get started. It will ask about the type of car you own, the mileage on it and any extra features it might have, such as a GPS system, MP3 player and so on. You can specify that it's a non-smoking vehicle or if you'll allow renters to transport their pets in it. As long as your car is safe and clean, it will probably be accepted for the service. You can even rent out a "clunker" if it's still fairly reliable.

Once you fill out a quick online form, there may be a follow-up call from a service representative. Have your vehicle registration info handy. You'll also need to provide a color photo or two of your car.

Device Installation

Some services install a proprietary device on your vehicle, so it can be rented out without worrying about juggling keys. (Others require you to be available to hand your keys over to the renter.) The device functions as a GPS, in case the renter doesn't bring it back from some reason. The device also controls the door locks and an engine immobilizer. In some cases, the device is entirely accessible from the renter's smartphone. This step takes about a day to complete. You'll have to drop your vehicle off at a service center that's authorized by the rental agency.

Set Your Schedule

Now that your car is ready, you can decide when you want to rent it out. The services offer a signup sheet for you to set hours, days or weeks when your car is available to rent out. For example, if you only use the car to do your grocery shopping and errand running on Mondays, you can offer to have the car available the other six days of the week. You also get to decide how much you want to charge for an hourly rate. It usually ranges from $5 or $6 an hour for an older vehicle, up to $15 or $20 an hour for newer models with nice features. You'll then know when and where you have to leave the vehicle, so potential renters can pick it up when they need it.

Insurance Info

The rental companies carry hefty insurance policies to protect your vehicle. RelayRides.com insures every car for $1,000,000. This should have you more than covered, even if the renter totals your car. The downside to this is that there's a deductible you have to pay out of pocket in some cases.

Background Checks

It's unlikely that your car will be stolen if you rent it out to people through these services. Before someone can rent your car, the agency runs a background check on their driver's license, insurance info and so on. They check to see if the person has any outstanding warrants, and they charge them by credit or debit card. Considering that they have all of the renter's contact and financial information, it would be really stupid for someone to steal your car or trash it. They want the renters to take good care of your car, so they impose hefty fines or penalties if there's trash left in it or any damage occurs. And again, the insurance policy will cover any significant loss.

Making Cash

So how much extra money can you earn like this? It depends on your hourly rate and how often you can offer to rent your car out. Here's an example:

Let's say you rent your car out through RelayRides.com for $15 an hour. Out of that amount, 15 percent goes directly to RelayRides, and 20 percent goes to the insurance policy. You get to pocket the remaining 65 percent. If your car is rented out for 20 hours a week, you'll receive $195. That's a good amount of cash considering that your car would otherwise just be sitting in the driveway.