Prophetic Flamespeaker #106 from Journey into Nyx is a foil mythic card that currently sells for about $2.30 ungraded, with graded copies ranging from $9.20 at grade 7 to $16.00 at grade 9.5. A grade 9.5 copy sells for around $16.00, about 7× the $2.30 raw price, so high-grade copies are worth grading.