Cheapest priced copy (Tarkir: Dragonstorm): $3.49 at Card Kingdom, near mint, their price list as of .
Stormscale Scion 
Creature — Dragon · 4/4 · Mythic · Tarkir: Dragonstorm · #123
Flying
Other Dragons you control get +1/+1.
Storm (When you cast this spell, copy it for each spell cast before it this turn. Copies become tokens.)
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
4 printings · $3.49 to $7.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Tarkir: Dragonstorm Promos | 123p | Mythic | $4.49 | $3.49 |
| Tarkir: Dragonstorm Promos | 123s | Mythic | — | $7.99 |
| Tarkir: Dragonstorm | 123 | Mythic | $3.49 | $3.99 |
| Tarkir: Dragonstorm | 303 | Mythic | $4.49 | $6.99 |
4 rulings from Wizards of the Coast
- 4 April 2025The copies are put directly onto the stack. They aren’t cast and won’t be counted by other spells with storm cast later in the turn.
- 4 April 2025Spells cast from zones other than a player’s hand and spells that were countered or otherwise failed to resolve are counted by the storm ability.
- 4 April 2025A copy of a spell can be countered like any other spell, but it must be countered individually. Countering a spell with storm won’t affect the copies.
- 4 April 2025The triggered ability that creates the copies can itself be countered by anything that can counter a triggered ability. If it is countered, no copies will be put onto the stack.