It doesn't work 100% of the time. The cheapest in my hometown isn't even listed nor the next cheapest on their site and they will instead list gas stations that are more expensive in neighboring towns. I also checked the town I used to go to college at and they claim there are one too many Casey's in town than there are and they fail to mention either of the Sinclairs, Shell, or Cenex. I wonder how wide spread this issue is.