The Gardevoir EX (155 / 160) card can be found in the Primal Clash set.
Recently sold 10 times and based on those sales is worth around £6.40.
Currently, there are 9 open listings for this card on ebay.
This card sells in the range of £3.66 to £9.14, making it stable.
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.