I doubt you will ever see any Tesla chargers in the US, that have a slot or reader for a CC. Card readers can be skimmed, like many gas station pumps are. When you own or lease a Tesla, you need to link one of your credit cards to your car. When you plug your Tesla into a Supercharger, the car communicates with the charger and starts charging with the fees charged to the linked card. No other steps involved. Charging fees will vary, depending on what charger you are using. On this trip, they varied from .29 to .46 / Kwh. Now, some chargers are going to time of use charging so if you want to charge in the middle of the night, it could be even cheaper.