Cheapest priced copy (Urza's Saga): $0.35 at Card Kingdom, near mint, their price list as of .
Mobile Fort 
Artifact Creature — Wall · 0/6 · Uncommon · Urza's Saga · #303
Defender (This creature can't attack.)
{3}: This creature gets +3/-1 until end of turn and can attack this turn as though it didn't have defender. Activate only once each turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.35 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Saga | 303 | Uncommon | $0.35 | — |