Which Keldeo EX do you have?
Same name, 18× the price: $1.16 to $21 raw. The difference is printed on the card — it is just not somewhere most people think to look.
White Flare Japanese · #169
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$21
89% gem
Legendary Treasures · #45
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$4.92
9.8% gem
Black and White Promos · #BW61
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$3.11
13% gem
Boundaries Crossed · #49
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$1.98
43% gem
White Flare · #030
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$1.89
48% gem
White Flare Japanese · #027
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$1.45
74% gem
White Flare Japanese · #161
Check the set symbol in the lower right of the illustration, and the copyright year along the bottom edge. Those two identify the print run on every card that has them.
$1.16
90% gem
We have no hand-checked note for these printings yet, so the guidance above is the general rule rather than something specific to this card.
Prices are raw market value. Click a printing for its full grading verdict — the gem rate, the fees and whether it beats selling raw.