Cornerstone Mask Ogerpon ex #199 from Twilight Masquerade is a ultra_rare card that currently sells for about $3.76 ungraded, with graded copies ranging from $7.50 at grade 7 to $53.00 at grade 10. A grade 10 copy sells for around $53.00, about 14× the $3.76 raw price, so high-grade copies are worth grading.