Kingdra-GX #SM155 from SM Black Star Promos is a reverse holo promo card that currently sells for about $9.00 ungraded, with graded copies ranging from $13.00 at grade 7 to $115 at grade 10. A grade 10 copy sells for around $115, about 13× the $9.00 raw price, so high-grade copies are worth grading.