They arent commonly sold but ive seen them for sale as low as 12-13k before covid\2019-2020. Hard to say exactly what its worth with no information about the car. 20k may not be a bad buy if its got proper service history and a pre-purchase check comes out decent. Its certainly not a bargain given the very low demand for these, very hard to sell.
Cars like these only makes sense if you financially comfortable enough that you can pay someone to handle the repair and maintenance costs, or that you are skilled and knowledgeable enough to buy parts and perform required work yourself.