Cheapest priced copy (Magic 2015): $0.35 at Card Kingdom, near mint, their price list as of .
Inferno Fist 
Enchantment — Aura · Common · Magic 2015 · #150
Enchant creature you control
Enchanted creature gets +2/+0.
{R}, Sacrifice this Aura: This Aura deals 2 damage to any target.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2015 | 150 | Common | $0.35 | $0.49 |
| The List | M15-150 | Common | $0.35 | — |
2 rulings from Wizards of the Coast
- 18 July 2014As soon as Inferno Fist leaves the battlefield, its power bonus stops applying. This means that if you sacrifice Inferno Fist before combat damage is dealt, perhaps to destroy a potential blocker, the creature that was enchanted won't have the bonus when it deals combat damage.
- 18 July 2014If another player gains control of the enchanted creature, or if Inferno Fist becomes attached to a creature another player controls, Inferno Fist will be put into its owner's graveyard as a state-based action.