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 - $31,700
Lightly Played - $25,300
Moderately Played - $22,200
Heavily Played - $19,000
Damaged - $15,800
Near Mint Spanish - $31,700
Lightly Played Spanish - $25,300
Moderately Played Spanish - $22,200
Heavily Played Spanish - $19,000
Damaged Spanish - $15,800