Cornerstone Mask Ogerpon ex #199 from Twilight Masquerade is a holo ultra_rare card that currently sells for about $4.99 ungraded, with graded copies ranging from $13.00 at grade 9 to $33.50 at grade 10. A grade 10 copy sells for around $33.50, about 6.7× the $4.99 raw price, so high-grade copies are worth grading.