Cheapest priced copy (World Championship Decks 2001): $0.99 at Card Kingdom, near mint, their price list as of .
Blood Oath 
Instant · Rare · Mercadian Masques · #177
Choose a card type. Target opponent reveals their hand. Blood Oath deals 3 damage to that player for each card of the chosen type revealed this way. (Artifact, battle, creature, enchantment, instant, kindred, land, planeswalker, and sorcery are card types.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.99 to $27.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Mercadian Masques | 177 | Rare | $1.29 | $27.99 |
| World Championship Decks 2001 | jt177sb | Rare | $0.99 | — |