Real costs of a “fuel filling” at a price of e.g. 50ct/kWh

Hello, I don’t have a Tesla yet, but I would like to inform myself before. Suppose my Tesla has a range of 600km and the tank is at 0km. Now I am tanking at an e-charging column at a price of 50kWh. What does that cost me then? According to my calculations about 20 Euro. Can that be?! With billing method..[Translation adapted by Motor-Talk.]