If going minimally.
Assuming everyone already has a couple of warm clothing items in the closet.
First you'd need gaiters, because without gaiters snow will fly into your boots; second, you need crampons and thus boots with stiff soles. In Alpina they had -50% sales, you could get them for 80 euros. Ice axe for demanding ascents (MM, Vrtača, ...), since normal pants aren't good, you also need good pants with gaiters and base layer pants. For windbreaker, I wouldn't pay 300 euros, since you can get one for 40 euros, underneath wear something normal (warm)... with some writing about XXXX figure, I don't know if you're rich or have 1500 euro salary.
In nice weather you can do the tour even with normal clothes. I, for example, went to Raduha in tracksuit pants and over them rain pants, likewise to Sv. Višarje - result was great, it worked super; you're wet in any pants.
Sometimes I rode a motorcycle, and one evening outside it was -17 C; I dressed over ski suit, gloves that said -40, scarf and helmet - some XX rags, but I rode like that for years on motorcycle without problems, never froze.
Still, try some easier winter tour and later you'll come to the conclusion yourself what all you need. Everyone buys this themselves, some spend 400 euros, others 3000 euros for gear. It's like this: I'm sort of half-born mountaineer, this today's snow doesn't surprise me, outside barely +1C, but I was already wandering outside in the snow picking mushrooms. Even some wind that constantly blows up here doesn't surprise me. Our air and mountain air have no difference, but there is a difference between ours and valley air. To continue, when you have crampons, ice axe, clothes, gaiters, you also need knowledge when it's safe to head to the mountains; right after snowfall normally no, snow needs to settle, but since even this gear won't suffice you'll have to buy again shovel with probe, some snowshoes, touring skis... always something. Still adding my opinion: I wouldn't head to MM, Vrtača without experience, at least some winter course that's organized these days.