What kind of gas does a bug Volkswagen take?

Clean gasoline for street automobiles, and "regular" is fine. Don't put aviation gasoline in one; there's lead you don't need in it, there's octane you don't need in it and the fact no one paid road tax on it means it's illegal to use it in a car anyway. Besides, car engines run terrible on it. Don't use racing fuel either; it's also tax-exempt hence not to be used in a road car.