Cheapest priced copy (Mercadian Masques): $0.35 at Card Kingdom, near mint, their price list as of .
Inviolability 
Enchantment — Aura · Common · Mercadian Masques · #23
Enchant creature
Prevent all damage that would be dealt to enchanted creature.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
1 printing · $0.35 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Mercadian Masques | 23 | Common | $0.35 | $4.49 |