The Gengar (20 / 62) card can be found in the Fossil 1st Edition set.
Recently sold 12 times and based on those sales is worth around £21.17.
Currently, there are 23 open listings for this card on ebay.
This card sells in the range of £9.01 to £33.33, making it quite volatile.
This Rare card was illustrated by Keiji Kinebuchi.