Mario Kart Tour is a free game for iOS and Android. I think if you go on the Play Store or App Store and just type Mario Kart, you should be able to get it for free

Guys, is there mario kart tour? I wanna speedrun all cups. (RECENT UPDATE, THIS REPLY WAS POSTED IR 19:05 PM THURSDAY 2023 20TH OF SEPTEMBER)

You should ask in the mario kart series forum

https://www.speedrun.com/series/mario_kart

Mario kart is seperated from the other mario games here