Cheapest priced copy (Double Masters 2022): $1.99 at Card Kingdom, near mint, their price list as of .
Thousand-Year Storm 
Enchantment · Rare · Double Masters 2022 · #390
Whenever you cast an instant or sorcery spell, copy it for each other instant and sorcery spell you've cast before it this turn. You may choose new targets for the copies.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
8 printings · $1.99 to $9.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 286 | Rare | $1.99 | $2.49 |
| Double Masters 2022 | 390 | Rare | $5.99 | $6.99 |
| Double Masters 2022 | 545 | Rare | — | — |
| Foundations | 248 | Rare | $1.99 | $2.49 |
| Guilds of Ravnica | 207 | Mythic | $1.99 | $2.99 |
| Foundations Promos | 248s | Rare | — | $2.99Out of stock |
| Guilds of Ravnica Promos | 207p | Mythic | $2.79 | $9.99 |
| Guilds of Ravnica Promos | 207s | Mythic | — | $2.99 |
10 rulings from Wizards of the Coast
- 5 October 2018If the spell that's copied has an X whose value was determined as it was cast, the copies will have the same value of X.
- 5 October 2018If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copies will have the same mode or modes. You can't choose different ones.
- 5 October 2018The copies that Thousand-Year Storm's ability creates are created on the stack, so they're not "cast." Abilities that trigger when a player casts a spell (such as that of Thousand-Year Storm itself) won't trigger.
- 5 October 2018Copies are created even if the spell that caused Thousand-Year Storm's ability to trigger has been countered by the time that ability resolves. The copies resolve before the original spell.
- 5 October 2018Spells you've cast that were countered were still cast, and so will add copies when Thousand-Year Storm's ability resolves for later spells in the turn.
- 5 October 2018The copies will have the same targets as the spell they're copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. The new targets must be legal.
- 5 October 2018You can't choose to pay any additional costs for the copies. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.
- 5 October 2018If an effect instructs you to cast multiple spells, they're cast one at a time in any order.
- 5 October 2018Thousand-Year Storm's ability will copy any instant or sorcery spell, not just one with targets.
- 5 October 2018If the spell has damage divided as it was cast, the division can't be changed (although the targets receiving that damage still can). The same is true of spells that distribute counters.