The Gengar EX (114 / 119) card can be found in the Phantom Forces set.
Recently sold 7 times and based on those sales is worth around £36.24.
Currently, there are 21 open listings for this card on ebay.
This card sells in the range of £18.19 to £54.29, making it quite volatile.
This Rare Ultra card was illustrated by Ryo Ueda.
The fact that it is a EX card makes it one of the more valuable cards.