Grookey #SWSH001 from SWSH Black Star Promos is a reverse holo promo card that currently sells for about $6.63 ungraded, with graded copies ranging from $29.58 at grade 9 to $31.00 at grade 10. A grade 10 copy sells for around $31.00, about 4.7× the $6.63 raw price, so high-grade copies are worth grading.