Former Union 76 station (Monticello, IA)
This is a bit more interesting.
It seems that when Unocal sold their downstream assets in 1997 and pulled out of the midwest, a scrappy bunch of stations in Iowa and Wisconsin pulled together and rebranded as something called "Petro Stop." I've come upon several Petro Stop locations in my travels, and only one of them was still pumping gas.
This Petro Stop in the small city of Monticello (pop. 3796) is still in business as a service garage, but the storage tanks have been exhumed and the pumps are gone. Funny that no one's taken the price board down, then.