Cheapest priced copy (March of the Machine Commander): $10.99 at Card Kingdom, near mint, their price list as of .
Hedron Detonator 
Creature — Goblin Artificer · 2/3 · Rare · March of the Machine Commander · #31
Whenever an artifact you control enters, this creature deals 1 damage to target opponent.
{T}, Sacrifice two artifacts: Exile the top card of your library. You may play that card this turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $10.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine Commander | 31 | Rare | $10.99 | — |
| March of the Machine Commander | 118 | Rare | $10.99 | — |
4 rulings from Wizards of the Coast
- 14 April 2023If you don’t play the card, it will remain exiled.
- 14 April 2023Playing the card exiled with Hedron Detonator follows the normal rules for playing that card. You must pay its costs, and you must follow all applicable timing rules. For example, if the card is a creature card, you can cast that card by paying its mana cost only during your main phase while the stack is empty.
- 14 April 2023Unless an effect allows you to play additional lands that turn, you can play a land card exiled with Hedron Detonator only if you haven’t played a land yet that turn.
- 14 April 2023You may play the card exiled with Hedron Detonator even if Hedron Detonator leaves the battlefield or you lose control of it.