Which Dialga 1st Edition Holofoil do you have?
Same name, 18× the price: $7.06 to $124 raw. The difference is printed on the card — it is just not somewhere most people think to look.
Legendary Shine Collection · #017
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.
$124
65% gem
Intense Fight in the Destroyed Sky · #071
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.
$7.19
51% gem
Dialga Half Deck · #007
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.
$7.06
42% 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.