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 - $15.400
Lightly Played - $12.300
Moderately Played - $10.800
Heavily Played - $9.300
Damaged - $7.700
Near Mint Spanish - $15.400
Lightly Played Spanish - $12.300
Moderately Played Spanish - $10.800
Heavily Played Spanish - $9.300
Damaged Spanish - $7.700