The Giratina V (SWSH259) card can be found in the Swsh Black Star Promos set.
Recently sold 22 times and based on those sales is worth around £3.84.
Currently, there are 9 open listings for this card on ebay.
This card sells in the range of £2.24 to £5.44, making it very stable.
This is a Promo card.
The fact that it is a V card makes it one of the more valuable cards.