Mana Vault doesn't untap during your untap step. At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault. At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you. {T}: Add {C}{C}{C}.
NM-Mint - $60.30
Lightly Played - $57.20
Moderately Played - $54.20
Heavily Played - $48.20
Damaged - $39.20
NM-Mint Non English - $60.30
Lightly Played Non English - $57.20
Moderately Played Non English - $54.20
Heavily Played Non English - $48.20
Damaged Non English - $39.20