Cheapest priced copy (Ravnica: Clue Edition): $0.59 at Card Kingdom, near mint, their price list as of .
Firespout 
Sorcery · Uncommon · Shadowmoor · #205
Firespout deals 3 damage to each creature without flying if {R} was spent to cast this spell and 3 damage to each creature with flying if {G} was spent to cast this spell. (Do both if {R}{G} was spent.)
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $0.59 to $7.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ravnica: Clue Edition | 190 | Uncommon | $0.59 | — |
| Commander 2011 | 199 | Uncommon | $0.59 | — |
| Shadowmoor | 205 | Uncommon | $0.59 | $7.99 |
| From the Vault: Annihilation | 6 | Mythic | — | $1.49 |
3 rulings from Wizards of the Coast
- 8 June 2016This spell cares about what mana was spent to pay its total cost, not just what mana was spent to pay the hybrid mana symbol in its cost.
- 8 June 2016This spell checks on resolution to see if any mana of the appropriate colors were spent to pay its cost. It doesn’t matter how much mana of that color was spent; the effect isn’t multiplied.
- 8 June 2016If this spell is copied, the copy will not have had any colors of mana paid for it, no matter what colors were spent on the original spell.