https://www.techradar.com/news/mario-kart-tour-beta

The next Nintendo mobile game, Mario Kart Tour, is officially out, but only in closed beta in the US and Japan and only on Android. Players and news outlets have already reported it’s a faithful 3D racing experience...with microtransactions and multiple in-game currencies.

That’s right – it’s free to play, at least in this beta version. It’s important to remember that the game may change based on feedback, especially its monetization, though Nintendo doesn’t shy away from the roulette-style “gacha” item buying, which appears again in Mario Kart Tour.