Cheapest priced copy (The List): $0.35 at Card Kingdom, near mint, their price list as of .
Golem's Heart 
Artifact · Uncommon · Scars of Mirrodin · #161
Whenever a player casts an artifact spell, you may gain 1 life.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.35 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| DCI Promos | 60 | Rare | — | $0.59 |
| The List | SOM-161 | Uncommon | $0.35 | — |
| Scars of Mirrodin | 161 | Uncommon | $0.35 | $1.49 |
2 rulings from Wizards of the Coast
- 1 January 2011Whenever a player casts an artifact spell, Golem’s Heart’s ability triggers and goes on the stack on top of it. It will resolve before the artifact spell does.
- 1 January 2011Unlike Golem Foundry and the Smith cycle, Golem’s Heart’s ability triggers whenever any player casts an artifact spell, not just when you do.