During yesterday's Nintendo Direct Pokémon Shuffle a free-to-play match-3 puzzler was announced for Nintendo 3DS. The game will be a free download and you will be able to play it in its entirety without microtransactions, but in-game purchases will allow for boosts or extra hearts (much like King's free-to-play puzzle titles on mobile).
Nintendo have previously tested the business model with Steel Diver, but clearly a puzzle game has more potential to break the ice as a free-to-play title on 3DS. Pokémon Shuffle will launch on eShop next month.