Mana Echoes #136 from Double Masters is a foil mythic card that currently sells for about $59.34 ungraded, with graded copies ranging from $25.00 at grade 9 to $28.00 at grade 9.5. A grade 9.5 copy sells for around $28.00 vs $59.34 raw. That's a modest premium, so grading only pays off for near-perfect copies.