By doing the same with a selection of goods made scarce in the pandemic, such as patio heaters and Pokémon trading cards, Max ended last year with a profit of more than $110,000 on $1.7 million in revenue, according to the 16-year-old’s sales records reviewed by The Wall Street Journal. He expects to do even better this year as game consoles and other products remain elusive.

“Some people call this retail arbitrage,” said Max, of Hopewell Township, in central New Jersey. “I wrote an essay for school on the topic.” 

The health crisis has triggered shortages of everything from ketchup packets to hot tubs, disrupting entire industries and frustrating consumers. It’s also supercharged the resale market, creating opportunities for Max and others to make a killing by flipping scarce items for big profits on Amazon, Facebook and other online markets. 

The reseller community has even become its own subindustry, with entrepreneurs—including other teenagers and young adults—paying for membership in online groups that offer tips.

Reselling nonessential goods in most cases is legal, though retailers generally frown upon it as it can create friction with consumers. Hate mail and trolling from shoppers angry about the marked-up prices comes with the territory. Max’s father, whose name is also Max Hayden, said he was initially uncomfortable with his son’s business success because he benefited from a situation created by the health crisis. But he concluded that it was permissible because his son only resells luxury goods, not necessities.