It is not totally unusual for public electric car charging stations to be free, especially if they are owned by nearby businesses. This acts as an incentive to park nearby, which has the knock-on effect of increased foot traffic for said businesses. However, the majority of these stations are pay-to-use. The total cost of using them is determined by a number of factors, the time of day and its geographic location. Users who own some form of membership get a slightly better deal, since they pay a flat monthly amount for usage fees as opposed to being charged each time they connect. Beyond this, users are charged either by the minute or for the session, regardless of length. Of the two plans, the former is more popular. Studies show that the cost of a public electric car charging station can be up to 50% higher than if you simply charge at home, which costs an average of $0.15 per kWh.