As long as Trinisphere is untapped, each spell that would cost less than three mana to cast costs three mana to cast. (Additional mana in the cost may be paid with any color of mana or colorless mana. For example, a spell that would cost {1}{B} to cast costs {2}{B} to cast instead.)
Near Mint - $18.100
Lightly Played - $14.500
Moderately Played - $12.700
Heavily Played - $10.900
Damaged - $9.100
Near Mint Spanish - $18.100
Lightly Played Spanish - $14.500
Moderately Played Spanish - $12.700
Heavily Played Spanish - $10.900
Damaged Spanish - $9.100