The Muk ex (96 / 97) card can be found in the Dragon set.
Recently sold 6 times and based on those sales is worth around £12.48.
Currently, there are 10 open listings for this card on ebay.
This card sells in the range of £6.37 to £18.59, making it quite stable.
This Rare Holo Ex card was illustrated by Hikaru Koike.
The fact that it is a EX card makes it one of the more valuable cards.