一瓶绿茶不要钱
[yī píng lǜ chá bù yào qián]
It humorously states, 'A bottle of green tea, don't ask for money'. It can indicate the user either values something as simple as free green tea, promotes a brand informally, or it's an idiom implying modesty and low cost or even a self-description of being casual or not greedy