God, I've been a Costco member for close to 10 years and I've never seen that big a discrepancy. I live in Maryland, just filled up yesterday at Costco for $3.47 and saw $3.49 on the way home. I remember seeing $0.10-$0.15 differences a few years ago and thinking that it was maybe worth it, but for $0.02 a gallon it…