The regular price of Coca-Cola 500 ml is 150 yen ($1.61 €1.21).
I bought a Coke for 100 yen ($1.08 € 0.81) from a vending machine. It is the cheapest price around my neighborhood.
In Japan, Diet Coke is called "Coca-Cola zero", zero means calorie zero.
Regular vending machines sell Coke for 150 yen ($1.61 €1.21).
If you want to know something, ask me please.