Brock's Onix #21 from Gym Heroes is a 1st edition rare card that currently sells for about $10.11 ungraded, with graded copies ranging from $10.00 at grade 7 to $84.55 at grade 10. A grade 10 copy sells for around $84.55, about 8.4× the $10.11 raw price, so high-grade copies are worth grading.