Cheapest priced copy (Urza's Saga): $5.99 at Card Kingdom, near mint, their price list as of .
Copper Gnomes 
Artifact Creature — Gnome · 1/1 · Rare · Urza's Saga · #291
{4}, Sacrifice this creature: You may put an artifact card from your hand onto the battlefield.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $5.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Saga | 291 | Rare | $5.99 | — |
2 rulings from Wizards of the Coast
- 4 October 2004You choose the artifact card on resolution.
- 1 May 2007Putting the card onto the battlefield is optional. When the ability resolves, you can choose not to.