Cheapest priced copy (The List): $0.35 at Card Kingdom, near mint, their price list as of .
Endoskeleton 
Artifact · Uncommon · Urza's Saga · #294
You may choose not to untap this artifact during your untap step.
{2}, {T}: Target creature gets +0/+3 for as long as this artifact remains tapped.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.35 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The List | USG-294 | Uncommon | $0.35 | — |
| Urza's Saga | 294 | Uncommon | $0.35 | — |