I have family members who live by this "Principle" where saving money is like an objective virtue, regardless of whether the item purchased is useful or good, or whether it was produced ethically, or whether the money they save will be used for anything of value.
I read a story about a Franciscan brother who tried to resist this "Principle" in his own life.  Anytime he felt he was stiffed by someone or shortchanged by an error, he would calculate the amount of money he lost and then donate that same amount of money to the poor or the church.