The Origin Forme Dialga V (177 / 189) card can be found in the Astral Radiance set.
Recently sold 25 times and based on those sales is worth around £35.00.
Currently, there are 81 open listings for this card on ebay.
This card sells in the range of £29.97 to £40.03, 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.