It started with a bag of used clothing that Bambi Falvo meant to donate.

“The bag was sitting in my bedroom awhile,” Falvo recalled. “And then my daughter came by and said, ‘How long is it going to sit there? You know you can sell it.’” Her daughter took Falvo’s cell phone and set up an account for her on Poshmark, one of numerous online sites that allow people to sell clothing — new, used and vintage.

Falvo started posting clothing for sale. “I started with gym clothing I wasn’t wearing anymore,” Falvo said. “It wasn’t high-end stuff.”

When a PINK sweatshirt sold for $16, said Falvo, “I was hooked, and then it escalated.” That was five years ago. Today, Falvo is an online entrepreneur who specializes in reselling new and used clothing.

She had not planned to start her own small business when she retired in 2019 after 32 years of teaching. Falvo’s last assignment was at PS 156 in Laurelton, Queens, where she taught universal pre-K, 1st grade and art. Fashion wasn’t on her radar — although she was voted Best Dressed when she graduated from Franklin K. Lane HS in Brooklyn in 1981.

Now, most of Falvo’s day is taken up with buying and selling. She said it is an ongoing lesson in fashion trends favored by a generation that has grown up with the internet and online shopping.

“I don’t wear vintage, but young people like the 1970s,” Falvo says. “I wish I had saved my Jordache jeans — the original, not the new ones out now. Or my marshmallow platform shoes.”

Vintage Levis are also a big seller, as are old rock band T-shirts. “It gives young people a connection to the past,” Falvo said.

She also looks for bargains at garage sales and flea markets, builds inventory by buying closeouts and liquidations, and sells on other online platforms, such as eBay and Depop. She has amassed a “whole inventory room” in her walk-up attic.

“It’s been a great supplement to my pension,” Falvo said.

Reselling fashions online helped her save money for the little extras in life, like dining out and home decorating. And six months ago, Falvo bought a house in Baldwin, Long Island, something she said she could not have afforded without her clothing business.

“Without the side hustle, I wouldn’t have decorated my new house as soon as I moved in or installed a pool in my backyard,” she said. “It’s a high to hunt for something, like hunting for gold. The more I’ve learned, the better I’ve gotten at finding stuff.”