Cheapest priced copy (Modern Masters 2015): $0.35 at Card Kingdom, near mint, their price list as of .
Worldheart Phoenix 
Creature — Phoenix · 2/2 · Rare · Conflux · #77
Flying
You may cast this card from your graveyard by paying {W}{U}{B}{R}{G} rather than paying its mana cost. If you do, it enters with two +1/+1 counters on it.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Conflux | 77 | Rare | $0.49 | $0.79 |
| Modern Masters 2015 | 135 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 1 February 2009As soon as you start to cast Worldheart Phoenix from your graveyard, the card moves onto the stack. At that point, it's too late for an opponent to prevent you from casting it by removing it from your graveyard.
- 1 February 2009If you cast Worldheart Phoenix this way, it is a spell and can be countered.
- 1 February 2009Casting Worldheart Phoenix from your graveyard by paying its alternative cost doesn't change when you can cast it. You can cast it only at the normal time you could cast a creature spell.