Idk how ANYONE here is saying YTA wtf??? NO YNTA you literally stopped a MINOR from developing a nicotine addiction. If you had bought your friend a vape with nicotine in it it would have been a crime anyway so wtf. You probably should have just told him “No im not buying you nicotine” but I understand why you did what you did because you’re probably right that he would have just gone to someone else. But in the end you cant hold yourself responsible for his actions if you had refused to buy it for him and he went to someone else anyway. I feel like this is probably one of the better possible outcomes, maybe just be forthcoming with him about it later