Cheapest priced copy (Edge of Eternities): $0.35 at Card Kingdom, near mint, their price list as of .
Roving Actuator 
Artifact Creature — Robot · 3/4 · Uncommon · Edge of Eternities · #157
Void — When this creature enters, if a nonland permanent left the battlefield this turn or a spell was warped this turn, exile up to one target instant or sorcery card with mana value 2 or less from your graveyard. Copy it. You may cast the copy without paying its mana cost.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Edge of Eternities | 157 | Uncommon | $0.35 | $0.49 |
5 rulings from Wizards of the Coast
- 25 July 2025If you cast a spell “without paying its mana cost,” you can’t choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the spell has any mandatory additional costs, such as that of Embrace Oblivion, those must be paid to cast the spell.
- 25 July 2025If you don’t want to cast the copy, you can choose not to; the copy ceases to exist the next time state-based actions are checked.
- 25 July 2025If the spell you cast has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 25 July 2025If an instant or sorcery card in your graveyard has {X} in its mana cost, X is 0 for the purpose of determining its mana value.
- 25 July 2025You cast the copy while Roving Actuator’s ability is resolving and still on the stack. You can’t wait to cast it later in the turn.