Alcohol is illegal in Saudi Arabia. All intoxicants are forbidden by the Qur'an and therefore under Islamic Law which Saudi Arabia follows alcohol is not permitted.
Zamzam Water- holy water from the Zamzam spring in Masjid al Haram believed to be divinely blessed is preferred among pilgrims to Mekkah.
There are many tea shops that serve tea and cookies. Also many juice vendors right outside the Mosque that sell Apple, Mango and Strawberry Juice for 1 SAR.