Is it permissible to donate to a hospital affiliated with a church that treats Muslims and Christians at symbolic prices?

Donating and giving charity to a disbeliever is permissible, and it becomes even more permissible if it is in return for a favor they have rendered. Indeed, the Prophet, peace and blessings be upon him, commanded that favors be reciprocated, even if they come from a disbeliever. An example of this is his saying concerning the prisoners of Badr: "Had Al-Mut'im ibn 'Adiyy been alive and then spoken to me concerning these foul ones, I would have left them for him." This was in reciprocation for his protection of the Prophet, peace and blessings be upon him.