Like many Gen Zers today, Audrey Finocchiaro and her then-boyfriend, Sam Lancaster, graduated from college a decade ago and were suddenly struck with harsh reality. The millennials had no money and no career direction—taking up serving and bartending jobs at local restaurants to make ends meet while crashing on her parents’ futon.

But they soon hatched a plan to get out of their 9-to-5 jobs: start a business by building a coffee cart with nitrogen-infused cold brew. So they started their own company, The Nitro bar, by maxing out a credit card to get things off the ground.

It was 2016 when the couple leveraged a $1,500 credit limit and scrap wood from Audrey’s parents’ basement to create a “glorified box” that would serve as their prototype. The cofounders packed into the back of Finocchiaro’s Subaru Outback and took off to Providence, Rhode Island. Their first makeshift cart had no electricity, only being able to hold the equipment used to make the cold brew.

To start reeling in customers, the couple would park the cart on city streets and at community events—often unsolicited—to sell their nitrogen-infused cold brew. In those early days, the business brought in $20 to $60 as the couple stood out there for eight hours daily.

Audrey Finocchiaro

At first, they became disheartened, as it was hard to make any profit at all. After weeks of little business, the couple was ready to throw in the towel.

But then Lancaster had an epiphany: he realized that they hadn’t brought the cart to Brown University yet. That fall, when college students flocked back to campus, they struck gold. They realized their key audience was a gaggle of Ivy League kids.

“‘Dude, you’ll never believe it!’” Finocchiaro tells Fortune, recalling what she reported to her boyfriend over the phone. “We just had a line of people. There were all these students, and I remember that day, I think we made like, $600 which was life-changing for us at the time.”

From that day forward, the couple popped up at Brown University every day, as coffee-chugging undergraduates huddled around their cold brew business. From then on, The Nitro Cart started gaining a following on social media, amassing 500,000 followers, while continuing to pop up at events.

But everything changed in the spring of 2017. When Finocchiaro and Lancaster were set up at a farmers’ market in Providence, they were approached by a pair of investors asking how much money they needed to grow. Finnochairo hadn’t thought the cart would turn into a business with bigger potential until that day.

The couple and investors created a spreadsheet together and calculated what The Nitro Cart could grow into based on a projected number of stands and accounts for wholesale customers. They crunched the numbers and said they needed about $150,000.

“The next day, we got that money, which was crazy,” says Finocchiaro.

Audrey Finocchiaro

Until then, they’d been brewing their cold brew coffee every night in Audrey’s uncle’s diner. But once the funding rolled in, they immediately set up a production facility and pivoted into wholesale, figuring it was the only way to survive the slow winter months. The money disappeared quickly—largely spent buying a $1,200 kegerator (a small refrigerator designed or adapted to hold a keg from which the cold brew could be dispensed) for each of the 60 wholesale accounts they got on board during their first year.

But The Nitro Cart got its second wind when a local bike shop in Providence offered them 200 square feet of space for $400 a month. They jumped on it, funding their first storefront by taking a steep 30% interest loan through Square.

Business skyrocketed after the loan, and now the Rhode Island coffee company brings in $4.5 million a year in revenue. It also has 80 employees working at its three brick-and-mortar coffee shops, production facility, and small coffee trailer. The company’s cold brew is available on tap at more than 50 other locations across Rhode Island and Massachusetts.

How TikTok helped turn a coffee cart into a multimillion-dollar business

With over 500,000 followers on TikTok and 130,000 on Instagram, there’s no question social media has been one of the key factors in The Nitro Bar’s continued success—but it didn’t happen overnight.

“We just threw a ton of things at a wall and kept going until we found something that stuck,” Finocchiaro says. “And for us, that took I think it was seven years until we really started to gain a significant following online.”

But today, she admits building out a following on social media is more important than ever. Her advice for new creators is simple: make a running list of ideas in your notes app, post multiple times a day, and stick to a routine to build momentum.

“I think it’s an incredible time to start a business, because it can cost $0 to start,” Finnochario says. “ You can have no money and start a TikTok or start an Instagram account. That was monumental for us.”

The Nitro Bar’s posts include trends of trying different coffee combinations, hacks on what to order, and sampling their favorite menu items. “How lucky are we to be alive at the same time as blueberry banana lattes,” one of the videos is captioned. It’s racked up 80,000 likes.

Ignoring boomers and friends helped get the business off the ground

Finocchiaro learned quickly who she wanted to share her business ideas with. “Ignore the boomers or your friends in sales,” she explained on TikTok.

“The second you tell someone who isn’t an entrepreneur what you want to do, they start questioning everything—‘Why a coffee shop? There’s already a million of them,’ or ‘If it were that easy, everyone would do it,’” she says.

Instead of letting doubt creep in from people who don’t understand the risks and mindset required to start something from scratch, she advises limiting those conversations altogether and suggests replying that you’re investing in the business for the long game and betting on yourself gives you a higher return.