What is the ruling on girls playing a shared game with boys in which dolls are dressed, and in-game purchases are made via mobile phone to obtain virtual, unavailable currency or upgrades?

It is not permissible to play the aforementioned game, as long as its prohibition has been established, even if it is free. A believer must preserve their time and utilize it for what benefits them in their religion and worldly life. For time is a great blessing, and a person will be questioned about it on the Day of Resurrection. The Prophet, peace and blessings be upon him, said: "The feet of a servant will not move on the Day of Resurrection until he is asked about five things: about his life and how he spent it; about his youth and how he wore it out; about his wealth, from where he acquired it and how he spent it; and what he did with what he knew." He also said: "Two blessings in which many people are deceived: health and free time."