The Garchomp & Giratina GX (247 / 236) card can be found in the Unified Minds set.
Recently sold 5 times and based on those sales is worth around £20.92.
Currently, there are 9 open listings for this card on ebay.
This card sells in the range of £12.70 to £29.14, making it quite stable.
This Rare Rainbow card was illustrated by aky CG Works.
The fact that it is a GX card makes it one of the more valuable cards.