Magearna #XY186 from XY Black Star Promos is a reverse holo promo card that currently sells for about $23.99 ungraded, with graded copies ranging from $15.20 at grade 7 to $290 at grade 10. A grade 10 copy sells for around $290, about 12× the $23.99 raw price, so high-grade copies are worth grading.