where can I buy flex fuel and is that different from regular gas
E85 is cheaper but you get poor fuel economy with it. Regular gas in most places is E10 87 octane. The E number tells you the percentage of alcohol.
Flex fuel is a designation for an engine which will use grades of gasoline containing different amounts of alcohol. Every gas station sells it, unless they only sell ethanol free fuel, but I've never seen one, except at a boat launch.