I bought an Ego 1100mah kit (charger, tank, and battery with case) for 9.99 off eBay including free shipping. I purchase eliquid from the local gas station for 4.25 a bottle (which is including tax) (they have cheesecake, I love it!) The battery lasts great, the tanks and chargers don't.. I find myself replacing a tank due to leaking on average of once every two weeks...so I have to buy more tanks, which I purchase in 10 packs for 13.00 (again on eBay) and the occasional battery charger for 2.00 a piece (those last about three or four months before needing replaced).
After 1 year of vaping I needed to buy a new battery.. so I got another kit for 8.99 w/0 the case - including free shipping..
all in all I spend in a month, eliquid included, less than one carton of off-brand cigarettes cost (which I was spending 27.00 per carton for off brand...and I used to go through a carton a week!)
That said, going through tanks can be a pain if nothing else, so I am considering buying a kanga tank at this point, which is why I am here to talk to others about whether or not they leak and how often they need replaced.. (I am not a repair man and have no intention of learning tank repair.. I just want one to last as long as a battery does!)
But yeah, if you play your cards right you will spend so much less than smoking!