I did the maths. I was a 2 pack a day smoker, spending about 4000$ -- actually thinking about it, it may have been closer to $6000 -- a year on cigarettes (6-9$ per pack, usually on the upper end in New Jersey) for a pathetically long time.
In the 1.5 years I've been vaping, I've spent about $800-$1000 on EVERYTHING. I own one unique "trophy" mod, my OKL-T20 box that I had commissioned (cost me about $200) and my other mods were no less than 60$ a piece (I have 3 mech mods) and my IPV3 was $150. I spend about 100$ on juice every 4-5 months (definitely depends on which companies I'm buying from, but I usually frequent MBV so that saves me a lot of money). My atomizers, all combined (Chimbus, IGO-L, Caterpillar, Doge, Doge 2, a couple ProTanks/AeroTanks, Subtank, Nautilus Mini), cost me no more than 220$. My building supplies/cotton/wire is basically a negligible cost, I bought 100 ft of 26 and 28 gauge Kanthal, and that spool has been going strong my entire vape career. In total I've spent about 50-60$ on batteries.
Re-doing the quick math, I find a number pretty close to 1k even. It might be slightly higher than 1k if you account random trips to B&M's and stuff, plus I went through a short-lived carto phase (before protanks were all the rage), and I probably spent about 60$ on junk gear back in the day.
So for me at least, I'm spending ~4x less than I did when I was smoking cigarettes per year. I assume that this year will be even less expensive because I am very satisfied with all my gear/atomizers, and if I was completely cut off of vaping supplies entirely I'd probably have enough juice/kit/stuff to last me a full year.