Cool Porygon #15 from Wizards Black Star Promos is a holo promo card that currently sells for about $57.25 ungraded, with graded copies ranging from $50.73 at grade 7 to $249 at grade 10. A grade 10 copy sells for around $249, about 4.3× the $57.25 raw price, so high-grade copies are worth grading.