Cheapest priced copy (Marvel Super Heroes Commander): $1.99 at Card Kingdom, near mint, their price list as of .
Ultron's Auxiliary 
Artifact Creature — Robot Villain · 1/1 · Uncommon · Marvel Super Heroes Commander · #669
Menace
Whenever another artifact is put into your graveyard from the battlefield or an artifact card is put into your graveyard from anywhere other than the battlefield, put a +1/+1 counter on this creature.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.99 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Marvel Super Heroes Commander | 669 | Uncommon | $1.99 | $0.99 |