Cheapest priced copy (Planechase): $47.99 at Card Kingdom, near mint, their price list as of .
Darksteel Forge 
Artifact · Mythic · Magic 2014 · #206
Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $47.99 to $99.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters | 248 | Mythic | $49.99 | $74.99 |
| Darksteel | 110 | Rare | $54.99 | $99.99 |
| Planechase | 111 | Rare | $47.99 | — |
| Magic 2014 | 206 | Mythic | $47.99 | $79.99 |
One ruling from Wizards of the Coast
- 7 August 2020Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to an artifact creature you control may become lethal if Darksteel Forge leaves the battlefield during that turn.