I get told about all my purchases. My first ego, all my juice, my Vamo v5, my MVP 2, more juice, my Nemesis, and my Kayfun. Same thing every time "you don't need it, stop spending money, blah blah". In one ear and out the other.
I've stopped asking, and just do it. I get 75 a month for my vape budget. If I spend it on a new shiny, or juice, or whatever, it shouldn't matter. It's better than the 250$ a month I was spending on smokes.
I've actually used the "we're not fighting about it. I bought it, it's done, the bills are paid" many times, and it's worked. Almost too well. When I told her I spent $37 on my Nemesis and $36 on my Kayfun within minutes of each other, all I got was a shocked eyebrow raise. No arguement, just went on about our business. And when I order my Aqua, more juice, and whatever else I order on the 1st of April, I'm sure there won't even be the eyebrow raise.
I'm not saying you have to be mean about it, but put your foot down and be done with it. Over time, it'll fade to her not even batting an eye anymore as long as bills are paid, food is in the house, etc.