Voltorb #100 from 151 is a reverse holo common card that currently sells for about $10,000 ungraded, with graded copies ranging from $12,500 at grade 9 to $13,750 at grade 9.5. A grade 9.5 copy sells for around $13,750 vs $10,000 raw. That's a modest premium, so grading only pays off for near-perfect copies.