Cheapest priced copy (Commander 2011): $0.49 at Card Kingdom, near mint, their price list as of .
Chorus of the Conclave 
Legendary Creature — Dryad · 3/8 · Rare · Ravnica: City of Guilds · #195
Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
As an additional cost to cast creature spells, you may pay any amount of mana. If you do, that creature enters with that many additional +1/+1 counters on it.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.49 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2011 | 189 | Rare | $0.49 | — |
| Ravnica: City of Guilds | 195 | Rare | $0.49 | $2.99 |
3 rulings from Wizards of the Coast
- 1 October 2005Chorus of the Conclave's ability works only while it's on the battlefield, so you can't use it to put +1/+1 counters on itself.
- 1 October 2005Chorus of the Conclave's ability applies to creature spells only as they're being cast. You can't pay mana to put counters on creatures being put onto the battlefield by an effect.
- 1 October 2005Chorus of the Conclave's ability combines well with the convoke mechanic, effectively letting you tap creatures to put +1/+1 counters on the creature with convoke that you're casting, if you choose to do so.