Cornerstone Mask Ogerpon ex #199 from Twilight Masquerade is a holo ultra_rare card that currently sells for about $4.06 ungraded, with graded copies ranging from $7.50 at grade 7 to $47.00 at grade 10. A grade 10 copy sells for around $47.00, about 12× the $4.06 raw price, so high-grade copies are worth grading.