I started vaping more than a year and an half ago, and I believe that now I'm "smoking" more, for less money! And mind, tobacco in Portugal is not that expensive - the brand I used to smoke costs 3.5 Eur (maybe around 4 dollars), and there a lot of cheaper brands...
- When I smoked, I used to go thru half a pack a day (Not because I wouldn't like to smoke a little more, but because I tried to restrain myself) I have a very little asthma, and was "allowed" by my doctor to smoke no more than four cigarrettes a day, so that the asthma would not get worse. Even so, I would never smoke less than half a pack...

So, 3.5 x 16 = 56 Eur spent a month with analogs
- When I started vaping, I dumped the analogs in maybe a day and an half. Now, the asthma seems to be gone (Never used the medication again), and, because I started feeling overall better, I gradually increased my "smoking" with the e-cig, without realizing it at first... I DO like to "smoke"

... so, today I'm vaping more than I smoked, closer to what would be compared to a pack a day of analogs (sometimes, even more). BTW, the '10ml bottle is about 10 packs' assumption seems to be correct for me too.. I go thru three or four 10ml bottles a month. Well, my Excel speadsheet does not lie: counting for batteries (maybe a pair every 3 months) and atomizers, and I'm only spending around 45 Eur a month now

.
So:
Smoking: 56 Eur/month, smoking only half a pack a day
Vaping: 45 Eur/month, vaping a "pack" a day
Health improvement: Priceless!!
Hope this helps to put things in perspective. It also accounts for the 'ban the e-cig' thing... money not spent by us vapers is money not stolen from us in tobacco taxes... and that IS, of course, their main concern!
