The BTS ARMY is coming to a city near you, armed with $5.3 billion in spending power

The 58-year-old was willing to make the trip without having secured concert tickets as she and her two daughters were looking forward to soaking up the pre-concert atmosphere and pampering themselves afterwards with Botox, haircuts and some ‌Korean barbecue.

Maria and her daughters are part of a global wave that analysts at NH Investment & Securities say could generate a windfall of 8 trillion won ($5.32 billion) across the 44 cities that will host BTS' world tour - a phenomenon that they have dubbed "BTSnomics."

"We don't do our hair in Canada," Maria said, emerging from a crowd of fellow ticketless "BTS ARMY" members waiting in the crisp air in downtown Seoul's Gwanghwamun Square 10 hours before the show. She added that because they were in Korea, they would treat themselves.

"For myself Botox, facials, Potenza and all that stuff," Herrera said. "And then we do our hair care here, like we do haircuts, we do our color and all that." She added ⁠that her crew also planned to travel to Toronto for another BTS concert.

 While turnout for Saturday's show fell short of the 260,000 that was projected, the real financial power lies with fans who are eager to spend on services and merchandise.

"Performances by artists with a global fandom like BTS do not end with ticket sales, but drive tourism consumption throughout the entire city," said Lee Hwa-jeong, a researcher at NH Investment & Securities, adding that the 8-trillion-won estimate included direct revenue and secondary consumer spending.

Past record-setting world tours by pop superstar Taylor Swift and British rock band Coldplay have also been credited for helping local economies, though economists have generally been skeptical about concerts or big sporting events providing more than a small boost to a country's economy.

BTS' world tour will kick off on April 9 in the South Korean city of Goyang and will make stops in Las Vegas, Los Angeles, London, Paris, Tokyo, Singapore and other major destinations.

Analysts have said ticket sales could rise as high as 2.7 trillion won because BTS plans to use a centralised stage for the shows, which would have no obstructed views ‌and could ⁠increase audience capacity.

South Korea is already reaping the benefits from BTS' Saturday reunion. The band had been on a hiatus of more than three years because some members needed to fulfill their mandatory military service.

In the week leading up to the free concert, sales of BTS merchandise - from glow sticks to blankets to dolls - rose 430% from a week earlier at Shinsegae Duty Free's headquarters in Myeongdong.

At the Lotte Department Store in central Myeongdong, revenue for the weekend jumped 30% from a year earlier; for Shinsegae, it jumped 48%.

The number of inbound tourists for the first 18 days of March was up ⁠32.7% from a month earlier, data from the Ministry of Justice showed, pushing up hotel rates in downtown Seoul.

Hotel rates in Busan, where BTS will perform in June, have surged as much as seven times at some venues.

Stephanie Gonzalez, another ticketless BTS fan from Mexico, said she flew in two weeks ahead of the concert to experience "ARMY life to the fullest."

"I've been visiting pilgrimage sites like the old BigHit ⁠office and Hakdong Park," the 25-year-old said, referring to sites famous among fans because BTS members had been seen there in the past.

"I wanted to experience every place BTS has been to make the most of this trip," she said, adding that she spent about 90,000 Mexican pesos ($5,028) altogether even after staying at a no-frills hostel.

And in addition to the tourism boom, local fans ⁠are getting in on the action.

Huirin, a Seoul resident in her 50s, says she took a cab to Gwanghwamun on Saturday after getting her hair done to "save some energy on commuting."

"Are you kidding me? No woman - I mean, no ARMY - would go to a BTS event without dressing up," she said as she proudly showed off the BTS merchandise in her bag and the purple shirt that she wore beneath a black outer layer.