Rayquaza-EX #XY66 from XY Black Star Promos is a reverse holo promo card that currently sells for about $16.70 ungraded, with graded copies ranging from $28.60 at grade 7 to $458 at grade 10. A grade 10 copy sells for around $458, about 27× the $16.70 raw price, so high-grade copies are worth grading.