Cheapest priced copy (Commander 2015): $0.35 at Card Kingdom, near mint, their price list as of .
Vow of Duty 
Enchantment — Aura · Uncommon · The List · #C15-84
Enchant creature
Enchanted creature gets +2/+2, has vigilance, and can't attack you or planeswalkers you control.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
11 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2015 | 84 | Uncommon | $0.35 | — |
| Commander 2021 | 110 | Uncommon | $0.35 | — |
| Commander Anthology | 29 | Uncommon | $0.35 | — |
| Commander 2011 | 36 | Uncommon | $0.35 | — |
| Commander Legends | 54 | Uncommon | $0.35 | $0.49 |
| Conspiracy | 87 | Uncommon | $0.35 | $0.79 |
| Explorers of Ixalan | 6 | Uncommon | $0.35 | — |
| Game Night: Free-for-All | 21 | Uncommon | $0.35 | — |
| Murders at Karlov Manor Commander | 89 | Uncommon | $0.35 | — |
| The List | C15-84 | Uncommon | — | — |
| Starter Commander Decks | 40 | Uncommon | $0.35 | — |