While floating around on the internet, I stumbled upon this ethanol free gas station finder. You select the state and it says what stations carry ethanol free fuel. I don't know how trustworthy it is and I noticed it does include marinas, but there are some regular gas stations in the mix. I've heard "pure gas" gets better MPGs, so I figured I would mention it here seeing that more MPGs is always a plus in this business. Cost effective? I don't know I don't have many "pure gas" stations up here in the sticks of NH. 
Ethanol-free gas stations in the U.S. and Canada
Ethanol-free gas stations in the U.S. and Canada