BTW: the beutiful Isetta pictured is a 'Standard' model with after-market White side walls. the Deluxe had a vent in the door and 2 wipers. The luggage on the rear was also after market.
The price for this car was $998.00 when new. I don't remember if that was for the 'Standard' of the 'Deluxe'.
It was chain drive and the 2 rear wheels had a much narrower track so that it wouldn't need a differential. Because of the one piece axle, it only had a brake cylinder an shoes on one wheel.
A model was made for the UK that only had one wheel in the rear. That was for favorable road tax. As it is still a motorcycle if it has 3 or less wheels.