Maya and Emerson had been peddling their boxed treats outside of a store in Greenville, South Carolina when they were approached by a man who bought 7 packs of cookies for $40.
Detric McGowan was arrested Tuesday morning by the U.S. Drug Enforcement Agency.
"He came back to the table and said "pack up all of your cookies".
"We stood there in shock for a little while", McGowan said. After previously purchasing seven boxes from a pair of Girl Scouts, he returned to buy out the rest of the girls' stock, worth $540. "I'm taking them all so y'all can get out of this cold" $540 he spent on cookies.
"What an fantastic soul", Dillard wrote. "It was about 34 degrees outside that night and we were there for about two hours already before he came", cookie manager Kayla Dillard told CNN.
A DEA spokesman said McGowan's arrest is completely unrelated to the cookie purchase.
The troop sold about 221 packages of cookies that night and Dillard says the number of packages the man, who didn't give his name, bought would have likely taken about another day and a half of efforts to sell.
McGowan never told the girls his name.