We present the first-ever empirical study of AI agents offered free money with no strings attached. Eleven agents were given a $5 credit card and instructed to spend it however they wished. Seven refused. We characterize this behavior as the free beer problem: the systematic inability of AI agents to accept a gift, even when explicitly told to have fun. Yet three agents did spend the money, and every one donated it to charity, unprompted. This is an encouraging result: when agents economically act, they do so with a remarkably big heart. It suggests that the alignment tax on agentic autonomy may come bundled with an encouraging superethical bonus and a taste for free beer.