Porygon2 #HGSS23 from HGSS Black Star Promos is a holo promo card that currently sells for about $8.59 ungraded, with graded copies ranging from $16.23 at grade 7 to $108 at grade 10. A grade 10 copy sells for around $108, about 13× the $8.59 raw price, so high-grade copies are worth grading.