Cheapest priced copy (The Lost Caverns of Ixalan Commander): $0.35 at Card Kingdom, near mint, their price list as of .
Oathsworn Vampire 
Creature — Vampire Knight · 2/2 · Uncommon · Rivals of Ixalan · #80
This creature enters tapped.
You may cast this card from your graveyard if you gained life this turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.35 to $4.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Jumpstart 2022 | 70 | Uncommon | $0.79 | — |
| The Lost Caverns of Ixalan Commander | 204 | Uncommon | $0.35 | — |
| Rivals of Ixalan | 80 | Uncommon | $0.35 | $4.49 |
2 rulings from Wizards of the Coast
- 19 January 2018Oathsworn Vampire's last ability cares only whether you gained life in the turn, even if Oathsworn Vampire wasn't in your graveyard when that happened. It doesn't care how much you gained, whether you also lost life, or even whether you lost more life than you gained.
- 19 January 2018Casting Oathsworn Vampire from your graveyard follows the normal rules for casting that card. You must pay its costs, and you must follow all applicable timing rules.