Ruth Williams met Romney earlier in the week and told him she was struggling after losing her job in October and caring for a sick son, CNN reported Sunday.
Romney recognized Williams at the Saturday event in Sumter and handed her several bills worth about $50 or $60, his aide said.
"He was kind to me," Williams said. "He held onto me and he made Gov. [Nikki] Haley and them come see about me."
She said Romney also sent South Carolina state treasurer Curtis Loftis over to meet her after the exchange. Romney's aide confirmed to CNN Loftis also gave Williams money.
The gift is notable from a candidate who has said he would not give away "free stuff" as president, CNN said.
"I know there are some people who run for president that will say, 'Hey, I'm going to give you more. I'll find a way to give you some more. I'll change the rules and give you more money,'" Romney said at a December event in Conway, N.H. "I'm not that guy. If there's a competition for who will give you the most free stuff, go vote for that guy."