Hard to say, because Mk1 CityStromers were never actually sold to the general public – only around 25 were built, with the majority going to utility company RWE as part of a trial.
70 Mk2 CityStromers were built, and again most of those were sent to utilities companies and energy providers in Germany to use however they wanted. These cars were returned to VW, however, and later sold to members of the public.
120 examples of the Mk3 CityStromer, which was developed in partnership with Siemens, were built between 1993 and 1996. These Golfs were actually offered for sale to the general public from the outset. As of 2017, it’s thought 50 were still on the road. It’s not clear how much VW charged for them back in the day, but no way were they cheap.