DD came home with an invite for a party. Her classmate is having a joint party with her younger sister and the invite has both their names on it. DD wants to get them both a present but I think I only need to get a present for the child in my DD's class, assuming that the younger child will get presents from her classmates. Am I being tight or is that acceptable? I'm on a bit of a budget and can't keep splashing out on unnecessary presents.