Cheapest priced copy (Onslaught): $0.35 at Card Kingdom, near mint, their price list as of .
Goblin Machinist 
Creature — Goblin · 0/5 · Uncommon · Onslaught · #204
{2}{R}: Reveal cards from the top of your library until you reveal a nonland card. This creature gets +X/+0 until end of turn, where X is that card's mana value. Put the revealed cards on the bottom of your library in any order.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Onslaught | 204 | Uncommon | $0.35 | $0.99 |
One ruling from Wizards of the Coast
- 4 October 2004If all the cards in your library are lands, X is zero.