Cheapest priced copy (World Championship Decks 2000): $23.99 at Card Kingdom, near mint, their price list as of .
Metalworker 
Artifact Creature — Construct · 1/2 · Rare · Urza's Destiny · #135
{T}: Reveal any number of artifact cards in your hand. Add {C}{C} for each card revealed this way.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $23.99 to $3099.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Destiny | 135 | Rare | $199.99 | $3099.99Out of stock |
| World Championship Decks 2000 | jf135 | Rare | $23.99 | — |
2 rulings from Wizards of the Coast
- 4 October 2004This is a mana ability. It does not go on the stack and can’t be responded to.
- 4 October 2004You can reveal zero cards to gain zero mana.