Every Costco member has had the conversation. Someone sees the line of cars wrapped around the Costco gas station and asks — out loud or internally — whether the wait is actually worth it. Whether the savings justify the time. Whether the membership fee is recovered just from fuel, or whether gas is just one piece of a larger value equation. Gas prices vary by state, county, city, and even neighborhood, so there's no set discount Costco offers compared to rival stations, but