There are a few of them currently for sale on EBay. The ones I looked at were in very good condition. The one with a side car currently has a bid of $2200. The one without a side car has a current bid of $1000.
I work at a car lot and we just got in a 1960's Harley Davidson Topper scooter. It was only made for 5 model years. It is a rare piece and in great condition, but I am not sure what we need to sell it for.