Cheapest priced copy (Alara Reborn): $0.35 at Card Kingdom, near mint, their price list as of .
Ethercaste Knight 
Artifact Creature — Human Knight · 1/3 · Uncommon · Modern Masters 2015 · #175
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Alara Reborn | 3 | Common | $0.35 | $0.49 |
| Modern Masters 2015 | 175 | Uncommon | $0.35 | $0.49 |
| The List | MM2-175 | Uncommon | $0.35 | — |