And one more question, can US west gas stations use domestic dual currency credit cards? I heard that it needs zipcode, which gas stations need this? I would like to ask all of you for help, thank you ?

I have filled up gas in San Francisco and Los Angeles several times, all of which are parked, picked up the fuel gun directly, pressed the button to add what kind of oil, and then started to add. After filling up, go into the toll booth or store inside and tell the clerk which gun it is, and then pay the money.

I always pay in cash at the counter and if there's any change, they will give it back to me.

Domestic VISA or MAS credit cards can be used. Some stores may require a passport.

Some support debit cards, credit cards cannot be charged, go to the front desk to prepay

I tried but couldn't use domestic cards. You need to go to the counter and buy your oil, tell him which pump and how much, he will recharge on the pump, you choose the right oil number, and then just fill up. If you can't finish, you can get a refund at the counter. Or buy a cash card and you can fill up by yourself. I haven't succeeded in using domestic cards.

Email swipe card chip, magnetic stripe needs to be swiped at the counter, a bit troublesome, suggest cash

The price of gasoline is higher when you use a credit card. My highest recorded price was in Kissimmee, FL. $3.39/gallon with a credit card and $2.39/gallon with cash.

Most can be used, some gas stations do not need that code, but generally you need to swipe twice, first swipe one dollar, then you can add gas after success, and finally swipe how much to add how much money.

Should I not prepay?

Sure. It was in the US West last month.