Want to save some money while your car sits at an airport parking lot?

You might get that chance starting this fall if you live in the Seattle area. FlightCar today announced that it is opening service in Seattle this fall, the company’s fourth market. It also announced $13.5 million in venture funding, including cash from GGV Capital, General Catalyst, Comcast Ventures, SoftBank Capital and First Round Capital. Celebs Ashton Kutcher and Ryan Seacrest also are backing the startup.

Total funding stands at $20 million for the company, which is led by two entrepreneurs who’ve barely held driver’s licenses for long: Rujul Zaparde (age 19) and Kevin Petrovic (age 20).

The company allows users to get free airport parking, even if their car is not rented during a trip. It is free to list a car for rent, with the service currently available at airports in Boston, L.A. and San Francisco.

Renters pay less than they do with traditional rental car companies, as little as $15 per day. Those under the age of 21 will be assessed an additional $25 per day fee. ($10 for those who are 21). Renters are limited to 100 miles of driving per day, and they can’t smoke in the cars, drive them outside of the country or participate in illegal activity. Liability coverage is included for each rental, and those with major driving violations in the past three years are prevented from renting.

Instead of attending Harvard and Princeton, the entrepreneurs decided to continue building FlightCar. The service launched 18 months ago, and now has more than 30,000 members in three locations.

“FlightCar has proven itself to be an innovative and bold addition to the sharing economy,” said FlightCar Co-Founder Zaparde. “We are disrupting the incumbent car rental industry, and we are building an increasingly sticky community marketplace for travelers exploring more suitable transportation options.”

We got wind of the company’s arrival back in March, with Zaparde telling us that “we hope Seattle helps lead the way in helping startups have the freedom to market new innovative sharing economy service models in the Pacific Northwest.” The company had been waiting until the city figured out its ridesharing regulations before committing to Seattle.

Editor’s note: The “sharing economy” will be one of the subjects of the GeekWire Summit, coming up on Oct. 2. Panelists include Sidecar CEO Sunil Paul; Couchsurfing CEO Jennifer Billock; Postmates CEO Bastian Lehmann and Rover CEO Aaron Easterly. Details and tickets here.