Cheapest priced copy (The Lost Caverns of Ixalan): $0.35 at Card Kingdom, near mint, their price list as of .
Sunfire Torch 
Artifact — Equipment · Common · The Lost Caverns of Ixalan · #167
Equipped creature gets +1/+0 and has "Whenever this creature attacks, you may sacrifice Sunfire Torch. When you do, this creature deals 2 damage to any target."
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderBrawlStandardPioneerModernLegacyVintagePauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan | 167 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 10 November 2023You don't choose a target for the triggered ability granted by Sunfire Torch at the time it triggers. Rather, a second "reflexive" ability triggers when you sacrifice Sunfire Torch this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.
- 10 November 2023The source of the damage is the equipped creature, not Sunfire Torch.