Kyurem-EX #BW37 from BW Black Star Promos is a reverse holo promo card that currently sells for about $4.95 ungraded, with graded copies ranging from $7.37 at grade 7 to $535 at grade 10. A grade 10 copy sells for around $535, about 108× the $4.95 raw price, so high-grade copies are worth grading.