Cheapest priced copy (Shards of Alara): $0.49 at Card Kingdom, near mint, their price list as of .
Sacellum Godspeaker 
Creature — Elf Druid · 2/2 · Rare · Shards of Alara · #146
{T}: Reveal any number of creature cards with power 5 or greater from your hand. Add {G} for each card revealed this way.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.49 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Shards of Alara | 146 | Rare | $0.49 | $1.49 |
3 rulings from Wizards of the Coast
- 1 October 2008You can activate this ability even if you have no creature cards with power 5 or greater in your hand, or you have some but choose not to reveal any of them. In those cases, the ability won’t produce any mana.
- 1 October 2008While you’re casting a creature spell, that card is on the stack, so you can’t reveal it with Sacellum Godspeaker’s ability to produce mana. You can, however, activate this mana ability and reveal that creature card from your hand before you begin to cast the card as a spell.
- 1 October 2008This is a mana ability. It doesn’t use the stack, and it can’t be responded to.