The Unown V (177 / 195) card can be found in the Silver Tempest set.
Recently sold 11 times and based on those sales is worth around £28.99.
Currently, there are 21 open listings for this card on ebay.
This card sells in the range of £23.66 to £34.32, making it quite stable.
This is a Rare Ultra card.
The fact that it is a V card makes it one of the more valuable cards.