Cheapest priced copy (Odyssey): $0.35 at Card Kingdom, near mint, their price list as of .
Thermal Blast 
Instant · Common · Odyssey · #224
Thermal Blast deals 3 damage to target creature.
Threshold — Thermal Blast deals 5 damage instead if there are seven or more cards in your graveyard.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
1 printing · $0.35 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Odyssey | 224 | Common | $0.35 | $1.49 |