i dont have a data plan myself so i want to use someone else's simcard to download the game app but my question is: If the game app is already on the memory of the phone, do you still need a dataplan to play the game?

From my info a game app is not the same as a news app that needs to be updated every second.
i heard app stores and telecom providers have some kind of lucrative deal

where they both benefit from and which is protected by codes to prevent
wifi download.