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 - $8.800
Lightly Played - $7.000
Moderately Played - $6.200
Heavily Played - $5.300
Damaged - $4.400
Near Mint Spanish - $8.800
Lightly Played Spanish - $7.000
Moderately Played Spanish - $6.200
Heavily Played Spanish - $5.300
Damaged Spanish - $4.400