I told the story before about how I was at Caesars and a lady had only one quarter left playing the 25-cent Wheel of Fortune progressive. She got all three symbols for a $10,000 win and had she had three quarters played it would have been, if I recall, about two million dollars. She cried uncontrollably while many of us standing around said that had she taken the time to change a dollar bill or put a dollar bill into the machine to play three credits she would have won zip.
Edited to add: By the way remember the Majestic Lions 2-million+ progressive at MGM Grand? It took years for the progressive to be hit on the single machine. But actually several players lined up all the lions but had only one dollar played and not three.