Cheapest priced copy (Outlaws of Thunder Junction): $0.35 at Card Kingdom, near mint, their price list as of .
Thunder Salvo 
Instant · Common · Outlaws of Thunder Junction · #150
Thunder Salvo deals X damage to target creature, where X is 2 plus the number of other spells you've cast this turn.
Legal inCommanderBrawlStandardPioneerModernLegacyVintagePauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Outlaws of Thunder Junction | 150 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 12 April 2024The value of X is determined only once, as Thunder Salvo resolves.
- 12 April 2024Thunder Salvo will count any other spells you’ve cast this turn. It doesn’t matter if the other spells resolved, didn’t resolve, were countered, or are still on the stack.