Freddo,
I have done the math for MY situation, and YES, e-smoking CAN be cheaper than real cigarettes. HOWEVER, this is really a personal calculation. Based on my read of forum entries and comments, everyone's need/use of the e-cig is not related to the amount of real cigarettes or strength of cigarettes they used to smoke. I think e-smoking is really the development of a NEW habit, which also just has happens to have the ability to replace another.
I used all-caps on the word "CAN" because, there also seems to be a side-habit which develops, which is the purchase of every available e-smoking device, juice, battery, and option. I myself am considering developing a support group for this side of this addiction.
If I stop adding to my collection, in a few months I will break even and actually start saving money. But again, this really is a personal evaluation. I think a person beginning down the e-smoking trail should evaluate their needs after the ... playing phase is over with. Then it's a safe bet that measurement of carts/liguid/batts/atomizers can more accuratly be made. One last thing that HAS to be considered is, the value of ones health. For me, even if my e-cig habit worked out to the same price as regular smoking, the e-cigs would win, because, a lung is DAMN expensive (and so is clothes cleaning, deoderizers, breath freshners, lighters, ashtrays, etc. (and GOOD RIDENCE)