If someone ever came up to me like that and was demanding a present, I'd smile, give em a hug and say happy birthday, there's your present. If they got indignant to me about it I'd simply say "You wanted a present, not an expensive present. I guess you better think about what you ask for before you ask for it. You'll live a very disappointed life otherwise." Walk off and listen to the resulting temper tantrum fading away into the background.
Kill em with kindness.
