Cheapest priced copy (Teenage Mutant Ninja Turtles): $0.35 at Card Kingdom, near mint, their price list as of .
Quintessential Katana 
Artifact — Equipment · Uncommon · Teenage Mutant Ninja Turtles · #23
Equipped creature gets +1/+1 and has "Whenever this creature deals combat damage, untap it and you gain 2 life."
Whenever a Ninja you control enters, you may attach this Equipment to it.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Teenage Mutant Ninja Turtles | 23 | Uncommon | $0.35 | $0.49 |