The Mew (9 / 53) card can be found in the Wizards Black Star Promos set.
Recently sold 57 times and based on those sales is worth around £20.13.
Currently, there are 30 open listings for this card on ebay.
This card sells in the range of £11.58 to £28.68, making it quite stable.
This Promo card was illustrated by Ken Sugimori.