Cheapest priced copy (Duel Decks: Heroes vs. Monsters): $0.49 at Card Kingdom, near mint, their price list as of .
Anax and Cymede 
Legendary Creature — Human Soldier · 3/2 · Rare · Theros · #186
First strike, vigilance
Heroic — Whenever you cast a spell that targets Anax and Cymede, creatures you control get +1/+1 and gain trample until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.49 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Heroes vs. Monsters | 11 | Rare | $0.49 | — |
| The List | THS-186 | Rare | $0.49 | — |
| Theros | 186 | Rare | $0.49 | $0.79 |
4 rulings from Wizards of the Coast
- 15 September 2013Heroic abilities will trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times.
- 15 September 2013Heroic abilities will resolve before the spell that caused them to trigger.
- 15 September 2013Only creatures you control when the heroic ability resolves will get the bonuses. Creatures that come under your control later in the turn will not.
- 15 September 2013Heroic abilities won't trigger when a copy of a spell is created on the stack or when a spell's targets are changed to include a creature with a heroic ability.