Something that simple would probably be appropriate. It is not unusual for people to give these kinds of simple gifts to a variety of service providers: teachers, doctors, nurses, postal carriers, etc. Personally, a therapist who wouldn't accept something that small has a stick up his ***. LOL! That said, some therapists have a stick up their ***, so if you are in doubt, you might want to ask about boundaries concerning small gifts of appreciation for Christmas.

Larger, more expensive gifts, I totally understand the boundaries for.

Only once did I give a therapist a gift. I think it was around Christmas although that was sort of coincidental. It was not entirely inexpensive but I wouldn't call it extravagant either. I happened upon something that just sort of spoke to me as completely symbolic of the work we were doing together, and I couldn't pass it up. It was hilarious when he opened it because I didn't have to explain the symbolism at all; he completely got it right away. He graciously accepted it and it still sits in his office. In my case, I knew he would accept it because he has quite a few gifts of varying types from clients in his office -- we had actually talked about them previously because some of them are rather amusing.