Excadrill ex #168 from Black Bolt is a illustration_rare card that currently sells for about $21.10 ungraded, with graded copies ranging from $23.57 at grade 9 to $27.00 at grade 10. A grade 10 copy sells for around $27.00 vs $21.10 raw. That's a modest premium, so grading only pays off for near-perfect copies.