Hey there, I completely realize this might be the millionth time those questions are asked but I haven't found specific answers on the problems I have, so please bear with me

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I've just started painting and really enjoy it, read losts of material on the subject but have two points that cause me stress - priming and varnishing. I ,as a person, like to have my miniatures painted and done with them, no future repairs needed(might be some sort of condition but let's not delve in this).
As for priming I've already tried the following brands: Vallejo, Novol, Rustoleum surface primer, Car Plan and some local brand I don't really remember. Out of these only the first two served as something more than easily-scratchable basecoat, I mean they were smooth and covered well but that's all they really offered. The most I've been impressed with is Vallejo,as the durability it offers is amazing, but my only complaint is the price and was wondering if there is a suitable alternative for the same price. Don't really want to sound cheap but I'd rather spend my money on miniatures if there is an alternative to some modelling supplies. So, is there any brand with the same properties as vallejo spray for the same price? Also, what's the difference between plastic primer and regular ?
Now on varnishes . I have no experience here, unlike above and really need some help. As far as I know the best varnishes are the polyurethane gloss ones. Locally I have the choice of the following brands: vallejo premium color 60ml bottles, winsor and newton galleria and typical floor varnish. Which one should I go for, but don't limit your suggestions to these brands only? And what's the difference between floor varnish and the brands designed for miniatures? Are the former chemically(?) designed to work with acrylic paints and are they too thick?
Thanks in advance, and forgive my English, it's not native for me !