The Costco gas guide 2026 comes down to a few simple questions: what is in the tank, how much less do members really pay, how do you pay at the pump, and when should you fill up. Today is October 22, 2026, with the holiday driving season ahead, so this is a good time to get the details straight. Costco's own page says very little about price, so we separate what Costco says from what independent guides report, and we flag anything that cannot be verified. What Costco Says Abo