The Shining Mew (40 / 73) card can be found in the Shining Legends set.
Recently sold 15 times and based on those sales is worth around £25.38.
Currently, there are 44 open listings for this card on ebay.
This card sells in the range of £15.52 to £35.24, making it quite stable.
This Rare Shining card was illustrated by Sanosuke Sakuma.