Cheapest priced copy (Commander 2014): $0.49 at Card Kingdom, near mint, their price list as of .
Warmonger Hellkite 
Creature — Dragon · 5/5 · Rare · Commander 2014 · #41
Flying
All creatures attack each combat if able.
{1}{R}: Attacking creatures get +1/+0 until end of turn.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2014 | 41 | Rare | $0.49 | — |
| Commander Legends: Battle for Baldur's Gate | 814 | Rare | $0.49 | — |
| Commander Anthology Volume II | 128 | Rare | $0.49 | — |
4 rulings from Wizards of the Coast
- 7 November 2014Each creature's controller still chooses which player or planeswalker the creature attacks.
- 7 November 2014If there are multiple combat phases in a turn, creatures must attack during each combat phase in which they're able to.
- 7 November 2014If, during a player's declare attackers step, a creature is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under that player's control continuously since the turn began (and doesn't have haste), then it doesn't attack. If there's a cost associated with having a creature attack, the player isn't forced to pay that cost, so it doesn't have to attack in that case either.
- 7 November 2014Only creatures that are attacking when the last ability resolves will get +1/+0. That is, activating that ability before attackers have been declared won't give the bonus to any creatures, including ones that attack later in the turn.