Three male teenagers came to the girls' Pontiac, Mich., stand July 18 asking to buy lemonade. Instead, one of them allegedly grabbed the Mickey Mouse jewelry box containing $40 in cash, The Detroit News reported.
Danielle Behan, the mother of one of the girls, chased the teens and with the help of a neighbor caught two of the suspects, who were arrested by police, the newspaper reported Saturday.
A third suspect was arrested a week later.
"My mom said 'Don't let one bad person ruin the fun,'" Behan's 9-year-old daughter Serena said.
The $1 a cup from sales, plus money from donations, is flowing into canisters on tables, the Detroit Free Press reported.
"We're close to $100! Some of it's going to charity and some to us," Serena said.
The girls plan to give some of the money to Goodfellows, a charity that distributes holiday gift boxes to children ages 4 through 13 in the Detroit area, the Free Press said.
"We want the children to understand that just because there's one bad person out there, there are a million good people," Danielle Behan said.