How does that work? GasBuddy.com tracks prices consumers have already seen at the pumps.
They must have informants at the retailers.
The price “alerts” they send out via smartphone are uncannily accurate, at least here in Indiana. Typically 2-3 hours advance notice.
I believe that it simply looks for sudden drops or increases (over a few cents) in a region. Not every company or station changes at the same time. There's often a 1-3 day lag for many to change, so when a sudden significant change happens, you can reap the benefits at a lagging or leading station. That's my guess, anyway.
(I often look on the gasbuddy.com map, and slide over to OKC, usually among the lowest in the US. There are stations there right now at 2.03... and others over 2.40)