Just checked Gas Buddy. Cheapest Regular in my vicinity is Ghetto BP at Hague & Sullivant, at $1.67. Conversely, their Premium is $2.37, a 70¢ difference.
The BP in Grandview is the closest station to me. Their Regular is $1.85, but their Premium is only $2.28 - only 43¢ difference.
So what gives with these places?