My wife says $0-20 is the normal range and $50 is too big and makes it look like we are trying to get special treatment. I think $50 isn't much at all given how much we are paying the daycare. I'd like for not everything that we're paying to be going to the executives at the top and to go directly to those who are doing the real hard work day in and day out.

Edit: To clarify I'm not saying it needs to be in cash. Just talking about the amount to spend on a once-per-year gift.

Edit2: He has had the same three teachers all year.