The Altaria ex (90 / 106) card can be found in the Emerald set.
Recently sold 8 times and based on those sales is worth around £29.50.
Currently, there are 4 open listings for this card on ebay.
This card sells in the range of £0.40 to £58.60, making it highly volatile.
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.