Teens are starting to shop again after their spending has hit record lows during the pandemic, and teen girls are leading the resurgence with a focus on fashion, according to Piper Sandler's "Taking Stock with Teens" report. The age group is on track to spend an average of $2,165 this year, and online fashion retailers and marketplaces including Shein, Princess Polly, Depop and Poshmark are finding fans.