没钱就是任性
[méi qián jiù shì rèn xìng]
A somewhat ironic play on the phrase about wealth allowing one to do what they want, but here it refers to acting carefree despite being poor, perhaps indicating that even when someone does not have money, there should be freedom or courage in life. However, this phrase may seem negative to some people, so it might come off as slightly sarcastic in tone.