Patty Angeles got the deal of a lifetime when she went shopping two years ago for secondhand furniture for her new apartment.

The 25-year-old from Austin, Texas picked up almost-new shelves — and a fiancé.

“We tell people we met on an app,” Angeles told MarketWatch.

That’s true, but not in the way most people think. Angeles and her husband-to-be Ben Vineyard made their match two years ago, not on Tinder IAC, -0.61%^[1]  or Bumble, but on an OfferUp, an app that allows users within a five- and 30-mile radius of each other to buy and sell items like used furniture, appliances and clothing.

Patty Angeles, a 25-year-old from Austin, Texas picked up shelves on an app for used goods — and a fiancé.

She turned to OfferUp after she had seen some shelves she liked at IKEA, but didn’t want to pay the $70 price tag. When she found the exact same shelves on OfferUp for $30, she messaged Vineyard, and arranged to pick them up in the parking lot of a nearby Walmart WMT, -0.73%^[2]

When she saw him standing in front of his car, she thought, ‘Oh my gosh, who is that?’ After she made purchased the shelves, she sent him a message: “Wanted to say you’re really cute and if you’re ever up to meeting outside of OfferUp, I’d love to!”

They bonded over pancakes on their first date and their mutual love of working in tech. Angeles works in software sales, and Vineyard is an engineer. They’ve used the app to save $3,000 in the last two years selling their old clothing, furniture, electronics and Angeles’ old jewelry and handbags.

See also: Instagram-savvy millennials humblebrag about their wealth on Bumble and Tinder ^[3]

Finding love on apps that aren’t matchmaking platforms isn’t totally unheard ^[4]of. Couples have formed after trading messages about Spotify playlists or flirting on Instagram FB, -3.03%^[5]   posts.

More than 38,000 wedding dresses were sold on the shopping platform Poshmark in 2018, a 71% increase on the year.

But Angeles and Vineyard are part of another trend: The growing market for gently-used secondhand items. The secondhand market was valued at $24 billion in the U.S. in 2018 and it’s expected to increase in value to...