You may choose not to untap Amber Prison during your untap step. {4}, {T}: Tap target artifact, creature, or land. That permanent doesn't untap during its controller's untap step for as long as Amber Prison remains tapped.
Near Mint - $0.50
Lightly Played - $0.40
Played - $0.40
Heavily Played - $0.30
Damaged - $0.30
Near Mint Non-English - $0.50
Lightly Played Non-English - $0.40
Played Non-English - $0.40
Heavily Played Non-English - $0.30
Damaged Non-English - $0.30