Cheapest priced copy (Shards of Alara): $0.35 at Card Kingdom, near mint, their price list as of .
Demon's Herald 
Creature — Human Wizard · 1/1 · Uncommon · Shards of Alara · #72
{2}{B}, {T}, Sacrifice a blue creature, a black creature, and a red creature: Search your library for a card named Prince of Thralls, put it onto the battlefield, then shuffle.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Shards of Alara | 72 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 1 October 2008You may sacrifice the Herald itself to help pay for the cost of its ability.
- 1 October 2008To activate the ability, you must sacrifice three different creatures. You can’t sacrifice just one three-colored creature, for example.
- 1 October 2008You may sacrifice multicolored creatures as part of the cost of the search ability. If you sacrifice a multicolored creature this way, specify which part of the cost that creature is satisfying.