Is it ethically appropriate for a client to buy their psychologist a gift? I have been having free psychology therapy in my school for almost one year. Now the therapeutic relationship is coming to end. I want to give a small gift to my therapist to show my gratitude when my therapy is over. 


Are psychologists forbidden from  receiving gift from clients by their ethical code?
Alternatively, under what circumstances would it be appropriate?
Here you can find an essay that discusses role of gifts in psychotherapy in great detail and from many different angles. 

Focusing on US, Canadian, and Australian ethics codes of professional societies, the author concludes that  


  Despite the prevalent belief to the contrary, there are no code of ethics or guidelines of major organizations that specifically ban gifts in therapy.


A synopsis of all the reviewed ethics codes can be found here.

In a summary of the ethical and therapeutical implications of gift giving during therapy he emphasizes that (small and appropriate) gifts may actually have a place in therapy and that therapists who rigidly decline them may endanger therapeutic success:


  Giving gifts is an ancient and common way to express gratitude, appreciation and love. Gifts in psychotherapy and counseling are very common and often take place around the holidays, in termination, at an important junction of therapy and with children-clients. Therapists have not only received gifts but have also been regularly engaged in gift giving to clients. Usually this involves symbolic gifts, greeting cards, transitional objects, souvenirs from vacations or educational material, such as books, audiotapes or CDs. While traditional psychoanalysis has frowned upon gift giving in therapy and many therapists are reluctant or afraid to talk about it, the fact is that most therapists practice it regularly and find it acceptable and helpful as long as the gifts are symbolic, nor too expensive and appropriate. Unlike commonly held beliefs, appropriate gift giving in therapy is neither unethical nor constitutes dual relationships. Uncritical and rigid across-the-board rejection of all gifts or putting in place "No gift policies" are likely to make clients feel rejected and humiliated, harm the therapeutic alliance and interfere with the therapeutic progress.