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 - $27.500
Lightly Played - $22.000
Moderately Played - $19.300
Heavily Played - $16.500
Damaged - $13.800
Near Mint Spanish - $27.500
Lightly Played Spanish - $22.000
Moderately Played Spanish - $19.300
Heavily Played Spanish - $16.500
Damaged Spanish - $13.800