By Jake Sauberman, deputy sports editor

It is an hour before the Boston Celtics tip off against the Miami Heat on March 26, a crucial game for two playoff-hungry teams. Eager fans are making their way toward TD Garden through North Station, ready to walk up the steps and see the famous Garden sprawled out in front of their eyes. For some, this is their first Celtics game, and they look down to realize they do not have any Boston gear to separate themselves from the common civilian grabbing coffee on the way home from work.

On their way up the stairs, they encounter a burly man behind a counter. Donning a green sweatshirt with Celtics’ point guard Isaiah Thomas’s face plastered on the front with long hair poking out of his Boston hat, Ross Henderson, vendor of discounted Celtics, Bruins and Patriots merchandise, stands waiting for such fans.

“I’ve been here since 2005 and I’ve been in the subway since 1991,” Henderson said. “My first carts were set up all over the city.”

Henderson started his Boston business enterprise using knowledge from his days running a newsstand in New York City in the late 1980s. Starting in the Back Bay station in December 1991, Henderson sold gloves, hats and scarves to before transitioning to sunglasses and T-shirts in the summer. Merchandise proved to be a niche market, one he identified right away.

“Most of the stations that I went into, there was nobody else doing it,” Henderson said. “People mostly just sold food. Food is easier to sell to the commuters because it’s a challenge to sell merchandise to the same people. Whatever they buy, it’s a one-time shot.”

Filling an unmet need in the market, Henderson realized he had something big on his hands. Consumer demand continued to increase, leading him to expand throughout the city.

“It started to multiply as the years went by: Downtown Crossing, Copley, Harvard, North Station, everywhere for a while,” Henderson said. “I was kicking butt.”

But expansion led to some growing pains. The logistics of the business became difficult for Henderson to control from afar, and the entrepreneur decided to go back to his successful roots and consolidate his business to the single North Station location.

With a knack for identifying a gap in the market, it wasn’t long before Henderson settled upon the optimal location, a place where shirts bashing NFL Commissioner Roger Goodell and declaring Isaiah Thomas the second coming of the messiah would fly off the shelves: the platform of North Station, just a stairway and a street away from historic TD Garden.

“Eventually it became harder to handle – it’s a cash business – and employees were tough to manage,” Henderson explained. “So I shrunk back down. Here, I was going to Celtics games and I realized nobody was doing this so I went to the T and said, ‘I can set up here,’ and that was back in 2005. They said, ‘Great,’ so I started to do it since then.”

With the Celtics and Bruins making simultaneous playoff runs in their respective leagues, one would think that the playoff buzz amongst Bostonians would similarly excite Henderson. However, that is not the case. Henderson said he feeds off the first timer, the budding Celtics fan who needs some gear to feel accepted by the zealous ranks of those who bleed green.

“More of the hardcore people go in the playoffs, and those people are less likely to buy my stuff than newbies,” he said. “Casual fans don’t have their gear yet. It’s more exciting for fans, but it’s not actually better for business. It’s actually worse.”

Regardless of the well-being of the teams across the street, Henderson stays true to the pillar of his business: Low prices.

“I sell stuff cheap,” Henderson said. “The way that huge crowds come through, I try to grab them all without having them wonder about price. I’m more into the quantity and selling in volume.”

With the team store charging $30 a pop for a generic Celtics T-shirt and Modell’s ringing up their hats for $25 apiece, Henderson offers an array of creative and unique designs for nearly half the price.

A customer in a black Nike sweatshirt and jeans walks up to Henderson’s stand. Heading to the Celtics game without a scent of green, he eyes the assortment of merchandise hanging from the makeshift wall.

“Do you have this in green?” he asked, pointing to a black Celtics T-shirt with a design unlike anything found in the team store.

“Of course,” Henderson responded, walking back to the wall and pulling back the shirt, revealing a stack of shirts of that design in both black and green. “That’ll be $15.”

The fan had already pulled out $30 in cash in anticipation. Subtly putting away the extra bills, the customer walked away with his newly purchased shirt with a smirk, as if he got away with theft.