K.C.
I did not expect one when I used to bring my daughter, but I did always provide one at my own kid's birthdays for all children in attendance, even infants. For the little ones, usually just a board book or a small stuffed animal. I'd give bubbles if they were a bit older (6+ months). I would not feel slighted at all though if my son was invited to a party and his little sister came along but didn't get a goody bag.