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 - $100.00
Lightly Played - $90.00
Moderately Played - $80.00
Heavily Played - $70.00
Damaged - $50.00
NM-Mint Non English - $100.00
Lightly Played Non English - $90.00
Moderately Played Non English - $80.00
Heavily Played Non English - $70.00
Damaged Non English - $50.00