The Mew (47 / 53) card can be found in the Wizards Black Star Promos set.
Recently sold 4 times and based on those sales is worth around £26.67.
Currently, there are 2 open listings for this card on ebay.
This card sells in the range of £12.29 to £41.05, making it quite volatile.
This Promo card was illustrated by Ken Sugimori.