You will have to do some research in your state, ethanol use varies by state.
For instance here in MN all gas is E-10 except for a few stations that carry 91 octane gas with no eth. this gas is only for classic cars and motorcycle/ boats ect. That doesn't stop me from using it though. Some states have a choice, some have ethanol just in the 87 octane gas.
I know Michigan gas is E10, even though some time ago our governor Granny mandated that all the stickers be removed from the pumps. I guess that's to cover the stations that didn't put the stickers on the pumps. E10 is the defacto standard. No getting away from it anymore, at least in the States.
1. because, from reading in this forum I am seeing a reduction in MPG
2. I want to see how high I can get my MPG in my Corolla
Although you can't test it because you can't get regular fuel. Your Toyota might be doing fine on E10. Toyota did a study and found that it did not have much effect on the small displacement motors. I looked and could not find it but here's another one that tested a Camry with no decrease if FE.