Like with just about
Like with just about everything else in life it depends. When you have to pay for the juice whether at home or away, the cheapest rate is probably at home at night. If you find a charging station that’s willing to supply you free at the moment, then of course that station is your best course. The cost of charging regardless of locale, depends on the network, location, time of day, and availability. A phone charger network app is best to help you with this.