HOUSTON -

A stranger's act of kindness caught an elderly woman by surprise while shopping at a Houston Walmart.

A bad knee makes if difficult for 83-year-old Margaret Harrison to get out much, but about twice a week, she drives herself to the Walmart at Beltway 8 and Westview.

"I saw him say something to the checker, but I didn't know what it was," said Harrison.

On Tuesday, Harrison said a nice man helped her load her groceries onto the turnstile, and what happened next caught her off guard.

"I pulled out my card to pay for my groceries, and she said, no honey, he's already paid for your groceries," said Harrison. "I couldn't believe it."

Harrison sid she left the store so surprised she didn't realize the full extent of the stranger's generosity until she got change.

When she looked at her receipt, she realized that she had been given change.

"The change I got was a little over $50. And I couldn't believe it," said Harrison. "That he had bought the groceries, that would have been kind. But I never had something like that happen to me."

Harrison called her daughter in tears. Her daughter was so moved, she contacted Local 2 hoping her message of thanks would be heard.

"I said, 'I don't know if I looked pitiful, or if I was kind to him and he was kind to me... and he wanted to do something,"' said Harrison. "I don't know why he did it, but it was so sweet. It really was."

Harrison said she is on a limited budget, but she is still hoping to spread a little extra cash with missions close to her heart, passing on the kindness of a stranger.