No one can we don’t know what you’re paying per Kwh.
It’s like asking us how much a kg of grapes will cost.
Essentially to work out how much it’d cost to fill a car is get its energy capacity ie 64kw, 44kw etc & multiply that by the cost per kwh at the time you plan on charging.
I charge 20:30 – 01:30 and I pay 5.5p/kwh so a 44kw battery would be
44 x 0.055 = £2.20
Thats a rough idea as there are losses due to heat etc plus you’ll rarely need to charge from zero to full.
Calculation works the same for public chargers, look up the cost per kwh & multiply that by how much you’re going to take.