What is the best deckbuilding card game for beginners?

Across mainstream reviewers and specialist communities, Dominion 2nd Edition is the most frequently recommended entry point: the one-action / one-buy turn structure is simple to teach, and the 2nd Edition cleaned up rules text and swapped out weaker cards. Star Realms is the other common beginner pick because it's cheap, fast, and rules-light, though it's strictly two-player head-to-head.