>Most people in the world just buy their petrol per liter directly ... It depends. Here (Italy) most petrol stations are self-service/with automated machine f

>Most people in the world just buy their petrol per liter directly ... It depends. Here (Italy) most petrol stations are self-service/with automated machine for payments. If I buy in cash I buy gasoline "per money", i.e. 20 Euro or 50 Euro, you don't have any alternatives if not multiples of the bills. If I buy paying with a card then I still try (roughly) to meet the amount. I am not really aware that today 50 Euro will give me (say) 27.476 liters while last week (still say) it gave me 27.187 liters.