I look at certain items and try to do a cost vs. utility estimate. I don't really have a need for a weapon-mounted light and I certainly won't pay $50 or more for one.
Nor will I buy a handgun specifically because it has an "accessory" rail. If I did buy one, it would because that particular gun might be designated the SHTF weapon and there could conceiveably be utility for one gun to have a light.
That does not mean I won't pay $65 for a hand-held, high powered Sure-Fire light though. There I can see the utility since it can be used without the weapon for many other purposes. And it can serve as a "tac light" if needed.
Along that line - when it comes to rifles I weigh the utility to the disadvantages too. I've seen AR's with so many aluminum rails and do-dads they outweigh an M14. All that weight for a poodle-shooter? The AR was supposed to be
lightweight. If I buy a scope it should fit the useful range of the caliber. Why buy a 8-20x scope for a 5.56mm when I'd only use it out to about 300m? That scope on the '03A3 makes more sense to me.
Nor will I buy el-cheapo items like nylon holsters that are no more than a gun-shaped pouch. Good, functional holsters are fine. They don't need to be leather though, or skin from some exotic animal.
When it comes to ammo, I balk at buck-a-bang "defensive" ammo, especially in 20-round boxes. When I can get 50-round boxes of it cheaper, I do. Or I'll buy a different brand that has a good reputation even if it's an "older" design (e.g. Silvertips, Hydrashok).
How many magazines? My base comfort level is 3 mags per gun. One in the gun and a pair of backups. I have 4 1911's so that's 12 mags (mostly Wilsons). I've had cheap old GI magazines that work fine too and they're keepers. For something like a battle rifle, being able to carry 120 rounds ready to use is plenty. Though one seldom hears complaints about having too much ammo or too many magazines.
Certain guns I view as "luxury" guns that I'd certainly love to own, were it not for their prices. I'd love to own a replica of Quigley's Sharps 1874 but at $3300, I'd have to win the lottery first. Even Shiloh's "Business Rifle" at $1800 fits in that category. When it comes to handguns, I can't see paying more than about $1200 for one unless it is exceptionally well crafted or beautifully engraved.
Yeah, I'd like to be able to own a few nicely engraved carry pieces. Where's my lottery ticket?
But I'd rather buy four or five other guns for the cost of one engraved one. Engraving a gun doesn't make it shoot any better than a plain Jane.
Someone once said that you can judge a laborer or craftsman by the quality of the tools he uses. I think that is true. If you take your firearms use seriously, it'll show by the type and quality of the products you use.