Cheapest priced copy (The Brothers' War Commander): $2.79 at Card Kingdom, near mint, their price list as of .
Mirrorworks 
Artifact · Rare · The Brothers' War Commander · #149
Whenever another nontoken artifact you control enters, you may pay {2}. If you do, create a token that's a copy of that artifact.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $2.79 to $9.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Brothers' War Commander | 149 | Rare | $2.79 | — |
| Commander 2018 | 211 | Rare | $3.99 | — |
| Mirrodin Besieged | 114 | Rare | $3.49 | $9.99 |
4 rulings from Wizards of the Coast
- 1 June 2011The copiable values of the token's characteristics are the same as the copiable values of the characteristics of the artifact it's copying.
- 1 June 2011As the token is created, it checks the printed values of the artifact it's copying, as well as any copy effects that have been applied to it.
- 1 June 2011If the artifact that caused Mirrorworks's ability to trigger has already left the battlefield by the time the ability resolves, you can still pay {2}. If you do, you'll still put a token onto the battlefield. That token has the copiable values of the characteristics of that nontoken artifact as it last existed on the battlefield.
- 1 June 2011Each time the ability triggers, you can pay {2} only one time to get one token.