Brock's Sandslash #23 from Gym Heroes is a 1st edition rare card that currently sells for about $12.62 ungraded, with graded copies ranging from $12.15 at grade 7 to $39.00 at grade 10. A grade 10 copy sells for around $39.00, about 3.1× the $12.62 raw price, so high-grade copies are worth grading.