Which Espeon ex do you have?
Same name, 166× the price: $3.86 to $640 raw. The difference is printed on the card — it is just not somewhere most people think to look.
Unseen Forces · #102
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.
$640
2.8% gem
Prismatic Evolutions · #155
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.
$282
29% gem
Terastal Festival ex · #211
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.
$70
87% gem
Scarlet & Violet Promos · #SVP 175
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.
$20
60% gem
BREAKpoint · #52
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.
$17
12% gem
The Best of XY · #045
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.
$14
75% gem
Prismatic Evolutions · #034
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.
$5.30
48% gem
Terastal Festival ex · #063
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.
$3.86
85% 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.