Lost Ark is free-to-play. You can download the game on Steam. You can purchase Starter Packs on Amazon.com (granted via a Steam key) or directly from Steam.
Where can I play Lost Ark for free?
Players can download Lost Ark for free from Steam or the game’s website right now, having unlocked for everyone after a brief exclusive window for Founder’s Pack members. You can find more details on getting into Lost Ark early here.