Cheapest priced copy (Duel Decks: Sorin vs. Tibalt): $0.35 at Card Kingdom, near mint, their price list as of .
Coal Stoker 
Creature — Elemental · 3/3 · Common · Time Spiral · #150
When this creature enters, if you cast it from your hand, add {R}{R}{R}.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
4 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Sorin vs. Tibalt | 49 | Common | $0.35 | — |
| Dominaria Remastered | 114 | Common | $0.35 | $0.49 |
| Time Spiral | 150 | Common | $0.35 | $0.49 |
| Time Spiral Remastered | 159 | Common | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 8 December 2022If a token is created that's a copy of Coal Stoker, the token wasn't cast, and Coal Stoker's ability won't trigger. Similarly, if an effect copies Coal Stoker while it's on the stack, the copy becomes a token, but the copy was created on the stack and not cast from your hand, so the ability won't trigger in that case either.
- 8 December 2022Coal Stoker's ability isn't a mana ability. It uses the stack and can be responded to.
- 8 December 2022If a nontoken creature enters the battlefield as a copy of this creature, the copy's enters-the-battlefield ability will still trigger as long as you cast the spell that became that nontoken creature from your hand.