I first noticed this about a month or so ago. The 15% ethanol blend gas was more expensive than the non-ethanol. This morning when I filled the truck I saw that the 87 Octane Blend was 10 Cents more expensive than the 89 Octane pure gas.
$3.09 87 Octane 15% ethanol
$2.99 89 Octane pure gas
Another benefit is that my truck has had the check engine light on for almost 2yrs. Checked it and it is the engine knock sensor. After using non-ethanol for several weeks the light went out.