Cheapest priced copy (Modern Horizons 3): $0.35 at Card Kingdom, near mint, their price list as of .
Unstable Amulet 
Artifact · Uncommon · Modern Horizons 3 · #142
When this artifact enters, you get {E}{E} (two energy counters).
Whenever you cast a spell from anywhere other than your hand, this artifact deals 1 damage to each opponent.
{T}, Pay {E}{E}: Exile the top card of your library. You may play it until you exile another card with this artifact.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 3 | 142 | Uncommon | $0.35 | $0.49 |
| Modern Horizons 3 | 421 | Uncommon | $0.49 | $0.79 |
| Modern Horizons 3 | 514 | Uncommon | — | $0.49 |
3 rulings from Wizards of the Coast
- 7 June 2024You pay all costs and follow all normal timing rules for cards played with Unstable Amulet's last ability. For example, if the exiled card is a land card, you may play it only during your main phase while the stack is empty.
- 7 June 2024If Unstable Amulet leaves the battlefield before you play the most recently exiled card, you can play that card for as long as it remains exiled.
- 7 June 2024Unstable Amulet's second ability counts any spells cast from zones other than your hand. These are usually spells cast from exile, the graveyard, or the command zone. It also counts spells cast from outside the game, such as spells cast with Wish or Garth One-Eye's ability.