Even when Monica Martino was “broke and couldn’t afford anything,” she loved roaming the stalls at New York City’s holiday markets.

“I used to walk around and just think it must be so magical for these people to be out here in these little jewel boxes selling their stuff,” she said.

Now Ms. Martino, 53, sits in a jewel box herself. Six years ago, she started a business, Lemon Zesty, making tote bags and other items printed with sassy images of her own creation. (She calls it “fresh art with a sour twist.”) This year, she was selling her wares in a stall at the Bank of America Winter Village at Bryant Park, one of New York’s largest seasonal markets, with some four million visitors.

Black Friday marks the start to the holiday shopping season, traditionally observed with bone-crushing, bargain-hunting trips to big retailers and department stores.