I just replied to an EA member who raised the question "What is the most cost-efficient way to convert money into personal health?" so I thought I'll share it with you.
I'm pretty biased as a social psychology student, but some measures translates to health (physical and mental) better than cigarettes...the measure that was most correlated with longetivity was relationships and friendships (quantity and quality. It says Longest Study On Happiness but it's not only happiness, it's also longetivity).
So I guess find an affordable social hobby where you can meet new and good people.
Dancing, singing, martial arts (Capoeira is very social), ball games, off course, volunteering (socially). For me it's improvization. :)
And even cheaper (but as far as I remember, less effective than socializing, still more effective than not smoking) - avoid long sitting. Sitting is deadly. Stand up and make a little walk every once in a while.