That PowerPoint Your Teen is Perfecting? It’s a Pitch Deck for Harry Styles Tickets.

“You always complain that I am grumpy,” one slide reasoned. “Harry Styles makes me happy.”

Among the additional bullet points: Mr. Styles promotes a healthy diet by singing songs with the names of fruit in the titles, such as “Kiwi” and “Cherry.”

“Totally unconvincing,” recalls her father, Neil Williams, a 45-year-old accountant and the target of the PowerPoint at their home in Sussex, England. He admires her efforts though, and concedes, “the arguments are quite funny.”

It may be a “sign of the times,” as one of his songs says, but economic disconnect is roiling the Harry Styles market. Tickets to see the British singer-songwriter, who is now playing to sold-out arenas in the U.S., can fetch hundreds of dollars, and resellers charge a bundle for even nosebleed seats. At the same time, the heartthrob’s fan base is full of teens and tweens still collecting allowances.

Determined young fans, nicknamed “Harries,” are taking on extra jobs, putting out change jars and aggressively lobbying their parents for a chance to watch Mr. Styles on stage.

Abbie lucked out when her dad found tickets for a London show next June for about $85, the most he would pay. She plans to wear a feather boa, like one Mr. Styles sported at last year’s Grammy Awards. “He’s fabulous and amazing,” she says of the star.

In Redondo Beach, Calif., Laurel Cox’s mom said no to buying tickets for one of Mr. Styles’s 15 Los Angeles area shows, where the cheapest seats approached $300.

“She’s 16, she can earn the money,” says Robyn Cox, who is 48.

Laurel picked up two babysitting gigs and placed an emptied pickle jar, labeled “HARRY FUND,” in the kitchen to collect loose change. Anyone asking what she wanted for her 16th birthday last month got the same answer: “Money for Harry.”

“She won’t even talk about the possibility of not going,” her mom says. “She’ll start crying.”

Laurel earned enough to buy a $250 ticket last week for a show early next month. “I’m just so excited,” says the teen, who is now weighing what colored boa to wear.

Erika Lang, a government employee in Silver Spring, Md., agreed to buy Harry Styles tickets for her teen daughter, with one condition. “If we were going to pay for it, I got to go,” says Ms. Lang, 50, who describes Mr. Styles as the most handsome person alive.

Molly Lang and her mother, Erika Lang. Ms. Lang agreed to buy her daughter Harry Styles tickets with one condition, that she would get to tag along. Amanda Andrade-Rhoades for The Wall Street Journal

Molly Lang, 16, left nothing to chance. When tickets became available, she left her parents hand-written minute-by-minute marching orders, titled: “Harry Presale Instructions.”

“At 11:45 am, log onto ticketmaster.com ON A COMPUTER,” she wrote in blue pen, capitalizing and underlining some parts. “At 12, it will ask you to ‘join queue.’ DO IT. As fast as possible.”

Ms. Lang found the concert “fantastic” and Molly appreciated her mom springing for hot dogs, gummy bears, a Harry Styles sweatshirt and Harry Styles poster. “I can’t really complain,” says the teen. Molly is now pressing her family to vacation in London next summer so she can see Harry Styles there, too.

Mr. Styles became famous in 2010 after judges on the British singing show “The X Factor” put him and some other contestants together into the boy band One Direction. It became an international hit, particularly among teenage girls, before breaking up in 2016. Mr. Styles has since released three solo albums and his song, “As It Was,” topped the Billboard Hot 100 chart for 15 weeks. He headlined Coachella in April dressed in a shimmering sequin jumpsuit, and he stars in a new movie, “Don’t Worry Darling.”

Tay Vasquez, who is 21, paid $160 to see Harry Styles last year and says resellers are hawking the same seats, at the Kia Forum in Inglewood, Calif., for more than $800 this year.

The barista is working extra shifts and plans to stand outside the arena on concert night and keep refreshing Ticketmaster for less expensive tickets. “Even 15 minutes after the show starts, I really don’t care, I just want to be there for at least the majority of it.”

This is the biggest year of Mr. Styles’ solo career, says Louie Dean Valencia, a history professor at Texas State University who starting in January will teach a college course called “Harry Styles and the Cult of Celebrity.” (It filled up instantly, he says.)

He says Mr. Styles interacts with his fans in a way many other artists don’t. His stage is in the center of the arena, and he has helped fans come out as gay or get engaged to be married: The singer handed his microphone to a concertgoer who got down on one knee and proposed to his girlfriend. (She said yes.) At a New York show last month, fans hoisted a sign that said their dad wasn’t talking to them because they spent all their savings on concert tickets.

“I have two things to say,” Mr. Styles responded from stage. “First of all, thank you very much. Secondly, very irresponsible spending.”