meal ticket 饭票

Meal ticket may refer to a) a ticket that entitles the bearer to meals in a specified restaurant, especially when meals purchased in this manner are offered at reduced rates; b) someone upon whom one is dependent for one's income or livelihood, for example, selfish children who look upon their father only as a meal ticket; or c) something, as an object or ability possessed by a person, that is necessary to that person's livelihood, for example, the radio announcer's voice was his meal ticket. (Source: reference.com)

Meal ticket（饭票）可指在指定餐馆就餐的餐票，以此种方式就餐通常可以享受折扣；或者指某人收入或生活的主要来源，如，自私的孩子们只是把自己的父亲当成了饭票；或指某人赖以生存的一个物品或一项技能，比如，电台播音员的声音就是他的饭票。