M.D.
Honestly, I don't think that you need to do gifts at all. I can understand your admiration for these ladies, but your son has only been going there for 3 months. That is not a long period of time. I would suggest that you have your son make each of the teachers a card or draw them a picture etc. That is a more than adequate gift considering the length of time he has been with them. If you feel more is in order consider having pizza delivered for that group of teachers or the class for lunch on his last day. I was a preschool teacher for many years and the handmade touches mean the most. If you don't want to order them lunch, you and your son can make them brownies or cookies. The gesture will be appreciated.