Black Kyurem #XY80 from XY Black Star Promos is a reverse holo promo card that currently sells for about $27.60 ungraded, with graded copies ranging from $59.95 at grade 7 to $2,820 at grade 10. A grade 10 copy sells for around $2,820, about 102× the $27.60 raw price, so high-grade copies are worth grading.