It actually is once you can get over some of the initial costs. I've spent one tenth as much as I would have smoking for two years. That's to say if I would have spent $2,000 in a year for cigarettes I've spent $200, or less on vaping per year.
Making my coils and using an RDA has cut back on costs too. I can get a 250 ft spool of Kanthal A1 26 awg wire, get roughly 600 coils out of it at around a whopping $0.02 for each coil. Granted, if I use SSL316, NiChrome I'll pay a little more. Then, I stop and consider "gee, $200 or less a year, sure I can spend a little more once in a while".
The biggest cost items are the mods, then batteries, wire, cotton/rayon, base juice, flavorings. I'm using a base juice of 100% VG at 18mg/ml nicotine. I've cut that down currently with some TFA Peppermint II at 10%, so I'm vaping roughly 90% VG/ 10% PG. I use it with sub-ohm coils.
Well hope you can find info you need. Apologies if I'm a bit brief.