Hi!
I dont want to start a rant, but.....
Why would you buy your instructor a pressie? You have been paying her/his wages for the last 50ish hours!? Its their job.... just like any other. You dont buy the airline pilot a bottle of whisky each time she/he lands you safely? Nor the traffic warden when they camp your car.
HOWEVER, before anyone calls me a scrooge - I am not against it. IF you have a certain, specific reason to say thnk you (i.e. helping though a difficult patch or whatever) then sure - but a "tradition"?
FW
P.S. Take it you have finshed the PPL then? CONGRATULATIONS!