FOILCheapest priced copy (Amonkhet): $0.49 at Card Kingdom, near mint, their price list as of .
Oracle's Vault 
Artifact · Rare · Amonkhet Promos · #234
{2}, {T}: Exile the top card of your library. Until end of turn, you may play that card. Put a brick counter on this artifact.
{T}: Exile the top card of your library. Until end of turn, you may play that card without paying its mana cost. Activate only if there are three or more brick counters on this artifact.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Amonkhet | 234 | Rare | $0.49 | $0.49 |
| New Capenna Commander | 374 | Rare | $0.49 | — |
| Amonkhet Promos | 234 | Rare | — | $0.49 |
| Amonkhet Promos | 234s | Rare | — | $0.49 |
8 rulings from Wizards of the Coast
- 18 April 2017If the card has X in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 18 April 2017If the exiled card is a land card, you may play it only if you have an available land play this turn.
- 18 April 2017The first ability of Oracle's Vault puts a brick counter on it even if you can't or don't play the card.
- 18 April 2017You may play the exiled card this turn even if Oracle's Vault is no longer on the battlefield or under your control.
- 18 April 2017If you cast a card “without paying its mana cost,” you can't choose to cast it for any alternative costs, such as emerge costs. You can, however, pay additional costs. If the card has any mandatory additional costs, such as that of Tormenting Voice, those must be paid to cast the card.
- 18 April 2017If you don't play the card, it will remain exiled.
- 18 April 2017Playing a card exiled with Oracle's Vault follows the normal timing rules for playing that card. For example, if the card is a creature card, you can cast that card only during your main phase while the stack is empty.
- 18 April 2017The cards exiled by Oracle's Vault are exiled face up.