I have given my T a Christmas present (~$20 value), a move to private practice card, and a book I picked up at thrift shop(just cuz), oh and a milkshake. She has accepted all of them. I've seen other things that I thought she'd like or would like to get for her but felt they were too expensive or something. I tend to kick myself afterwards when I do buy something for her.
So, if you want to, do so... and yeah if you have not talked about it with your T, be prepared for the full range of responses.
Oh and we've never talked about the why or urges around my gift giving.
I give it a 2-3 on the meter