Darksteel Forge #248 from Double Masters is a foil mythic card that currently sells for about $45.39 ungraded, with graded copies ranging from $35.00 at grade 9 to $39.00 at grade 9.5. A grade 9.5 copy sells for around $39.00 vs $45.39 raw. That's a modest premium, so grading only pays off for near-perfect copies.