90 octane ethanol free VS regular 87 octane

I wish I could purchase 90 octane gasoline without ethanol at the pump. My vehicles are fine with 87 octane with 10% ethanol, but not my 2 stroke rototiller. I just spent $4.80 for about a liter of premixed 90 octane fuel that contains no ethanol at a farm store for my rototiller.