Gandalf had spent considerable time consulting the menu. Given the lines, this was to be expected. Given that he had never been here before, it was even moreso. However, the wizard still had wound up essentially asking for whatever the server behind the counter felt was the best drink. Then, he'd turned, looking to the person behind him.
Gandalf considered this person for a relatively short period of time. He stared. He did some mental consideration, and then he turned to the counter again. "I shall be buying the next customer's order as well," he said, keeping his voice relatively low. He then took what was offered to him, which appeared to be coffee of some kind, and stepped aside.
The wizard kept his eyes upon the line, watching as the beneficiary of his charity stepped forward. While he watched, Gandalf drank. He gave the cup an appreciative look, and then took another sip, his eyes and attention focused.