Houndstone #42 from Scarlet & Violet Black Star Promos is a reverse holo promo card that currently sells for about $1.78 ungraded, with graded copies ranging from $7.60 at grade 9 to $22.50 at grade 10. A grade 10 copy sells for around $22.50, about 13× the $1.78 raw price, so high-grade copies are worth grading.