The Gengar (13 / 165) card can be found in the Expedition Base Set set.
Recently sold 1 times and based on those sales is worth around £28.50.
Currently, there are 2 open listings for this card on ebay.
This card sells in the range of £28.50 to £28.50, making it very stable.
This Rare Holo card was illustrated by Yukiko Baba.