Christmas Gifts!?

So my hubby and I want to get our son some presents for Christmas. We know he won't be too aware of anything, but we just thought it would be fun! That being said, he is only going to be 3.5 months on Christmas, so I am looking for some relatively inexpensive gift ideas that he can possibly even grow into throughout the year. Right now he seems to love anything that lights up or makes music. Appreciate any suggestions! ?