The Porygon-Z (100 / 100) card can be found in the Majestic Dawn set.
Recently sold 7 times and based on those sales is worth around £40.00.
Currently, there are 8 open listings for this card on ebay.
This card sells in the range of £27.15 to £52.85, making it quite volatile.
This Rare Holo Lv X card was illustrated by Ryo Ueda.