The Regirock ex (98 / 101) card can be found in the Hidden Legends set.
Recently sold 8 times and based on those sales is worth around £31.99.
Currently, there are 12 open listings for this card on ebay.
This card sells in the range of £21.71 to £42.27, making it quite volatile.
This Rare Holo Ex card was illustrated by Mitsuhiro Arita.
The fact that it is a EX card makes it one of the more valuable cards.