Can a single $100 bill solve an entire town's debt crisis? This riddle is a window into transaction costs. I rely on Jeffrey Rogers Hummel's insights, adding a few thoughts of my own. And a cool letter: Ever wondered why you haggle for a car but not for your morning Starbucks's coffee? Plus, a book recommendation: Nobel Prize-winning economist Edmund Phelps' "My Journeys in Economic Theory," a compelling read that blends economic insights with political theory.Links:David Henderson...