Don't waste you money on high octane fuel. The benefits are small, if any, and the only one who will be thrilled is the oil company you're buying the high priced stuff from. These little engines (you didn't tell us what you have) will run and perform just fine on low octane fuel. You need to be aware that the ethanol content will effect things like rubber or neoprene parts eventually. Fuel lines, gaskets, 'O' rings, etc will see a shorter lifespan the higher the alcohol content.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"