The Altaria ex (90 / 106) card can be found in the Emerald set.
Recently sold 1 times and based on those sales is worth around £14.57.
Currently, there are 2 open listings for this card on ebay.
This card sells in the range of £14.57 to £14.57, making it very stable.
This Rare Holo Ex card was illustrated by Ryo Ueda.
The fact that it is a EX card makes it one of the more valuable cards.