<human>: Could you distill the essence of the text into 1-3 sentences?

About a month ago, on my way out to class, an old lady was waiting inside a train station before the turnstiles. She only spoke Chinese and probably didn't have any money on her person. She asked everyone that walked by if they had an extra fare for her to get into the station. I happened to have a spare round-trip metrocard and I gave it to her. She thanked me as I left. Fast forward to today, again on my way to class, some lady walks out of the station with a metrocard in hand. "Are you going to take the train? Here take it, it's my monthly metrocard and it's expires today!" she says and hands me the card. Karma paid me back exactly $4.50.
<bot>: Gave $4.50 to an old lady for subway fare one month ago and karma returns my $4.50.