Self-Service Gas Station: Fueling and Paying: what to say in English

Excuse me, which button do I press for regular unleaded? I'm not sure which grade I need.

Ask when unsure about fuel type.

Do I pay first inside, or can I just tap my card at the pump?

Inquire about payment method options.

Fill it up with premium, please. Actually wait, I'll just put 50 bucks on it.

Change your mind about fuel amount.

Hey, the pump isn't working. It keeps saying 'see cashier.' Can you help?

Request assistance for pump issues.

Where's the air pump for tires? Is it free or do I need quarters?

Ask about tire air pump location and cost.

I'm on pump 3. Can I also grab a receipt?

Request a receipt after fueling.

Could you put 40 dollars on pump number 5? I'll pay cash.

Specify cash payment for a pump.

The receipt printer isn't working. Can I get one from inside?

Ask for a receipt if printer fails.