GasBuddy is great, no doubt! I was well familiar with them before working on the site. The issue is that their data is user reported and not directly reported from Costco's warehouse numbers - so there were a few times that the price was vastly different from what was at the pump.
replyWhen I first bought my current car, I downloaded GasBuddy, intending to use it to find the best gas prices and the reported prices on the app were uniformly wrong. After the first couple times I used it, I gave up and stopped using it.
replyThe user-reported vs source-reported thing is bigger than people think. I work with car listing prices and the gap between what people say something costs and what the source actually shows is basically the whole reason my product works. Pulling from the warehouse numbers is the right call even if the coverage is smaller.
replyIt's an extensive dataset (Gasbuddy is one of the most used apps in the US) and they have sophisticated techniques to prevent fake/incorrect prices. I've used it for years and have only come across incorrect prices twice.
replyCostco prices are great but it should not be used to calculate things like "average national gas prices". You will inevitably over-represent the types of places where Costcos are more likely to be built.