Cheapest priced copy (Adventures in the Forgotten Realms): $0.35 at Card Kingdom, near mint, their price list as of .
Rust Monster 
Creature — Beast · 2/1 · Uncommon · Adventures in the Forgotten Realms · #161
First strike
Sacrifice an artifact: This creature gets +2/+0 until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Adventures in the Forgotten Realms | 161 | Uncommon | $0.35 | $0.49 |
| Adventures in the Forgotten Realms | 321 | Uncommon | $0.35 | $0.49 |
| The List | AFR-161 | Uncommon | $0.35 | — |