Yekaterina Shneyderova, 22, found the money, all in $100 bills, along with financial records of a Marietta couple, while examining the box, The Atlanta Journal-Constitution reported.
Shneyderova, a Kennesaw State student, said as soon she saw the cash she knew she had to return it to the rightful owner.
"I saw the money and the envelope with an address and I thought it might be someone's life savings. I couldn't keep it, I couldn't do that," said Shneyderova.
She showed her find to Value Village District Manager Lance Letson. He took the money to the address on the envelope.
The cash box was owned by Ronald and Imogene Crowder, who had mistakenly donated it Tuesday to American Kidney Services, a charitable group working with Value Village.
Letson arranged a meeting between Shneyderova and the Crowders Saturday at the Roswell store. The Crowders gave Shneyderova a $200 reward for her good deed along with the cash box.