Cheapest priced copy (Battle for Zendikar): $0.49 at Card Kingdom, near mint, their price list as of .
Akoum Hellkite 
Creature — Dragon · 4/4 · Rare · Battle for Zendikar · #139
Flying
Landfall — Whenever a land you control enters, this creature deals 1 damage to any target. If that land is a Mountain, this creature deals 2 damage instead.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 to $2.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battle for Zendikar | 139 | Rare | $0.49 | $1.49 |
| Game Night 2019 | 36 | Rare | $0.49 | — |
| Battle for Zendikar Promos | 139s | Rare | — | $2.79Out of stock |
| Starter Commander Decks | 123 | Rare | $0.49 | — |
3 rulings from Wizards of the Coast
- 8 November 2024A landfall ability triggers whenever a land you control enters for any reason. It triggers whenever you play a land, as well as whenever a spell or ability puts a land onto the battlefield under your control.
- 8 November 2024Whenever a land you control enters, each landfall ability of the permanents you control will trigger. You can put them on the stack in any order. The last ability you put on the stack will be the first one to resolve (As a result, you can have those abilities resolve in the order of your choosing.).
- 8 November 2024A landfall ability doesn't trigger if a permanent already on the battlefield becomes a land.