The Vaporeon ex (110 / 113) card can be found in the Delta Species set.
Recently sold 2 times and based on those sales is worth around £49.40.
Currently, there is 1 open listing for this card on ebay.
This card sells in the range of £40.18 to £58.62, 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.