When I was in middle school, I remember reading what was, at that time, the most gruesome story I'd encountered in public school.  It was about a couple who were struggling with their finances, I believe.  The wife answers the door one day to find a man with a button under a glass top.  When pressed, she would earn an amount of money that would sufficiently aid their situation, but someone she did not know would die.  She takes the button, struggling as to whether or not to use the tool.  Her husband is strongly against it, the story revealing itself as a clash of ideologies.  When he goes to work, she presses the button, and her husband dies on the subway tracks.  She confronts the man who gave her the button, and he inquires of her, "Do you really think you knew your husband?"

Does anyone here recall the name and/or author of this story?  It's been on my mind, off and on, for months now.