Hmmm.. i've just sat and worked out, after looking at one of those NHS get unhooked adverts, that if I stopped smoking I won't really save that much. On average I go through 15 fags a day (sometimes less, sometimes more, so 15 is a decent average) so 15 fags a day, times 365 days a year shows me smoking 5,475 fags a year. So then I divided that by 20 (saying I brought packs of 20) and that shows I only buy 273 packets of 20 fags a year, totally (if £4.36 a pack) £1,190.28, and to be honest that really ain't a lot. I would work out how much I spend on alcohol but I'm too scared to find out the outcome of that! Though I haven't had a drink since last Friday (early morning). :p
So below you will see my wonderful algebraic calculation of how I worked it out.
(((x * 365) / 20) * y) = z
x = smoke a day
y = price of a pack of 20 fags (of your brand)
z = total cost