Those looking to save money on ever-climbing Metro fares are turning to the thrifty person's mecca: Craigslist.

The Washington section of the site posts offers to buy and sell SmarTrip cards or paper fare cards every day.

Gaithersburg resident Eddie Roza commutes from Shady Grove to Farragut West and started looking for discount SmarTrip cards online two months ago. He also has helped co-workers buy cards from Craigslist, he said.

"I'm spending like $320 a month. That's a lot. So I try to get them at a discount. I usually get them at 30 percent off," he said.

Many of the sellers on Craigslist say they are moving out of state and want to get rid of their cards. But they may be misguided -- Metro offers to refund fare cards for people who live more than 100 miles from Washington, spokeswoman Caroline Lukas said.

And buying is not without hazards. People selling Smar- Trip cards that are registered can report the card lost and get the balance wiped and transferred to another card -- as rider Rajan, who did not want his last name used, found out the hard way. He said he bought a $100 card only to see his balance suddenly drop to zero.

"I thought, 'Wow! How is that possible?' " he said. "I guess you can reassign money."

Others have figured out how to be careful. Roza said he buys only unregistered SmarTrip cards and paper fare cards. He meets the seller at a Metro station so he can check the card's value before buying.

Metro officials said reselling and buying used Metro cards isn't illegal -- but isn't encouraged.

"Buyer beware," Lukas said via email. "It is not illegal, but not something that we would recommend."

Lukas said she was not aware of any complaints about scams on resold SmarTrips.

SmarTrip card sales --mostly inauguration versions -- are also taking off on eBay. Some of the cards are selling for $20, with no mention of how much value is left on them. The original 2013 inauguration cards sold for $5, plus $25 worth of Metro fare.