Visitors to Washington state parks who don’t want to shell out $30 for an annual parking pass can earn one by volunteering 24 hours to clean beaches, build trails or plant trees.

The sweat equity is a little-known option for acquiring the permit required by the 2011 Legislature, the Seattle Times reported. Selling the passes helps raise money for parks and recreation areas overseen by the Department of Natural Resources (DNR) and the Fish and Wildlife Department.

“All of us are concerned about the notion some people can’t afford to go to parks,” said state parks spokeswoman Virginia Painter. “So this is a way we can provide something and get some support for the park system, since we’re mostly dependent on user fees at this point.”

Here’s how it works if you want to work 24 hours for a pass and earn the equivalent of $1.25 an hour:

Parks and the other agencies post cleanup or other work projects on websites. Volunteers also can check with rangers for opportunities. A ranger or other supervisor signs off on the hours. Volunteers do the work, mail in vouchers and receive a Discover Pass in return.

It’s not just a perk; it’s also kind of a merit badge, recognizing the service of volunteers who get their parking the old-fashioned way — they earn it.

About 500 complimentary parking passes were issued between July 2011 and September 2012. That compares with just over 1 million passes sold — about half were $30 annual passes and half were $10 one-day passes, Painter said.

The DNR and wildlife share in the revenue — 84% for parks, 8% for DNR and 8% for wildlife.

The passes are sold in stores that sell fishing and hunting licenses, and available online and through state-park offices. Parking without one could bring a $99 fine.

Officials hope more people buy the passes to help offset cuts in state funding.

In addition, the parks department is working on marketing campaigns. Painter said park users can watch for a gift pass in December for holiday shoppers. The agencies also are partnering with companies such as Subaru, where dealers give out passes with test drives.