Which Hydreigon EX do you have?
Same name, 25× the price: $1.50 to $38 raw. The difference is printed on the card — it is just not somewhere most people think to look.
White Flare Japanese · #171
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.
$38
90% gem
Super Electric Breaker · #133
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.
$23
91% gem
The Best of XY · #099
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.
$12
83% gem
White Flare Japanese · #163
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.
$5.22
92% gem
Super Electric Breaker · #124
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.
$4.87
91% gem
Roaring Skies · #62
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.
$4.70
7.5% gem
White Flare · #067
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.
$1.81
41% gem
Super Electric Breaker · #072
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.
$1.63
82% gem
White Flare Japanese · #062
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.
$1.50
72% 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.