$1.95 for regular today. Loading it into a rental car, so I was happy!
It's not too far from the strip and, honestly, if you're being a tourist, then you should go to the Ethel M (M&M Factory) before heading over here, and then head onto Boulder City and Hoover Dam after you re-fuel. Typical Costco rules: Use your Costco Amex card or your Costco card to start the transaction, and then pay with either your Costco Amex or Debit card. No cash.
Lines weren't that long on a weekday at around 11am. Also, if you don't want Costco food for a quick bite, there are other shops in the nearby area that you can try out. Starbucks is particularly close. (We went to a Panera Bread in the area).