Cast a random Lesson spell without paying its mana color. If that spell has X in its mana cost, X is 3. (As of today, there are 20 lessons. Perhaps look up a list and roll a d20?)
Near Mint - $45.500
Lightly Played - $36.400
Moderately Played - $31.900
Heavily Played - $27.300
Damaged - $22.800
Near Mint Spanish - $45.500
Lightly Played Spanish - $36.400
Moderately Played Spanish - $31.900
Heavily Played Spanish - $27.300
Damaged Spanish - $22.800