Cheapest priced copy (The List): $0.35 at Card Kingdom, near mint, their price list as of .
Zada, Hedron Grinder 
Legendary Creature — Goblin Ally · 3/3 · Rare · Battle for Zendikar · #162
Whenever you cast an instant or sorcery spell that targets only Zada, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
12 printings · $0.35 to $9.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Masters 25 | 156 | Uncommon | $0.39 | $0.49 |
| Battle for Zendikar | 162 | Rare | $0.49 | $0.99 |
| Commander Masters | 268 | Uncommon | $0.49 | $0.79 |
| Foundations Jumpstart | 76 | Rare | $0.49 | — |
| Multiverse Legends | 25 | Uncommon | $0.39 | $0.49 |
| Multiverse Legends | 90 | Uncommon | — | — |
| Multiverse Legends | 155 | Uncommon | — | $2.49Out of stock |
| Multiverse Legends | 155z | Uncommon | — | — |
| Battle for Zendikar Promos | 162s | Rare | — | $4.99 |
| The List | A25-156 | Uncommon | $0.35 | — |
| Secret Lair Drop | 2406 | Rare | — | $9.99 |
| Secret Lair Drop | 2423 | Rare | — | $2.29 |
8 rulings from Wizards of the Coast
- 16 March 2018Any creature you control that couldn't be targeted by the original spell (due to shroud, protection abilities, targeting restrictions, or any other reason) is just ignored by Zada's ability.
- 16 March 2018If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copies will have the same mode. You can't choose a different one.
- 16 March 2018Zada's ability triggers whenever you cast an instant or sorcery spell that targets only Zada and no other object or player.
- 16 March 2018The copies that the ability creates are created on the stack, so they're not cast. Abilities that trigger when a player casts a spell (like Zada's ability itself) won't trigger.
- 16 March 2018If you cast an instant or sorcery spell that has multiple targets, but it's targeting only Zada with all of them, Zada's ability will trigger. The copies will similarly each be targeting only one of your other creatures. You can't change any of the copy's targets to other creatures.
- 16 March 2018The controller of a copy can't choose to pay any alternative or additional costs for the copy. However, effects based on any alternative or additional costs that were paid for the original spell are copied as though those same costs were paid for the copy.
- 16 March 2018If the spell that's copied has an X whose value was determined as it was cast (like Rolling Thunder does), the copies have the same value of X.
- 16 March 2018You control all the copies. You choose the order the copies are put onto the stack. The original spell will be on the stack beneath those copies and will resolve last.