Sidisi, Brood Tyrant #199 from Khans of Tarkir is a mythic card that currently sells for about $6.50 ungraded, with graded copies ranging from $12.80 at grade 7 to $72.00 at grade 10. A grade 10 copy sells for around $72.00, about 11× the $6.50 raw price, so high-grade copies are worth grading.