The Big Score Promos — mythic
$1.95 → $1.18, down 39% over 89 days
They range from $0.88 to $4.69 — a 5× difference for a card with the same name. The set code and collector number printed along the bottom edge are what tell them apart.
Not sure which one you are holding? OtterDex reads the set code and collector number off the card and tells you.
