Quit smoking cold turkey (was a 1 pack smoker for over 7 years). I am 3 days nicotine free and that sounds very interesting to me. Roadblocks: they keep selling them... If someone else is planning the same, the tips at whyquit.com helped me.
I didn't think it would work, originally, and bought it figuring that for $8, if I just skipped one pack of cigarettes it would've paid for itself. So far, I've gotten a roughly ~400x return on it (1 pack Marlboro Reds/day).