Cheapest priced copy (Magic Origins): $0.35 at Card Kingdom, near mint, their price list as of .
Fiery Impulse 
Instant · Common · Magic Origins · #145
Fiery Impulse deals 2 damage to target creature.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, Fiery Impulse deals 3 damage instead.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic Origins | 145 | Common | $0.35 | $3.99 |
| The List | ORI-145 | Common | $0.35 | — |
One ruling from Wizards of the Coast
- 22 June 2015Check to see if there are two or more instant and/or sorcery cards in your graveyard as the spell resolves to determine whether the spell mastery ability applies. The spell itself won’t count because it’s still on the stack as you make this check.