A functional magic item economy and price list would help immensely here. 5e punted on this one.
By 'functional', I mean rooted in the sort of quasi-barter system that would naturally arise when a) adventurers met other adventurers in town and the idea of trading items came up, and b) adventurers (or others) commissioned artificers to make items to order; eventually leading to a comprehensive price list that reflects each item's usefulness, rarity, ease of manufacture, raw material cost, and 'cool factor'. And this cannot be done by a formula.
The 3e and 4e price lists are not the least bit functional because they are done to a hard-coded formula which only looks at rarity and nothing else. This ends up with some fairly useless items being crazy expensive and very useful items being cheap as dirt (the poster children for the latter being Wands of CLW in 3e and Bags of Holding in 4e).
'Cause yeah, 5e treasure is pathetic as written. Every time I look at a 5e adventure or module with thoughts of converting it to run, the first consideration is how I'll have to up the treasure to make it worth the PCs' while to do it.
PF2e goes hard in this direction of high-level adventurer-relevant commerce, using a combination of levels, rarity and access. Items have levels and so do settlements, so for instance you're unlikely to find high-tier items in a level 5 fishing village (with some exceptions, such as if it's a port city not far from a metropolis that canonically has adventurers pass through it not infrequently, and therefore common consumables of up to level 10 are readily purchasable). Uncommon and rare items aren't necessarily
stronger than common items, but they may be tougher to find outside specific regions, or they may be mostly associated with specific organizations. In the default Golarion setting, for instance, there are specific areas where mechanical firearms have seen some manufacture, and they're not necessarily exported in large quantities; and likewise there are specific weapons which are associated with a notorious assassin cult which also happens to sharply disapprove of impersonators. So, there's level and rarity gating in addition to cost; and in PF2e, most magic items have specific costs (not vague ranges
) which escalate significantly with higher level.
So, a high-level character might find himself heading to a major city to acquire fancy gear, like armor made of exotic materials, high-tier magical runes, what-not. Some things are hard to find and may still require questing to acquire (and perhaps craft), but other items are effectively treated as off-the-shelf if you can find the right locale; but if you're in a survival-oriented campaign in the wilderness, you may not have that option and even relatively modest items may not be readily bought (and this is where the crafting subsystem most comes into play; it's really meant to provide
access to items, not
profit vs. purchasing).
AFAICT, the 2014 version of the DMG indicated that generally most magic items aren't readily available for purchase in D&D 5E. I'm not an FR lore nerd, though; and my impression is that it
is a fairly high-magic setting in certain places ala Waterdeep, so I'm not entirely sure how much it'd actually affect worldbuilding to readily allow purchasing magic items. I think that there's at least an implicit assumption that spell components are pretty available, despite the exotic nature for some (e.g. pickled tentacle and eyeball in a platinum inlaid vial that must have a (list? actual retail?) value of >= 400gp; that's a bit specialized), given that I don't think parties are generally expected to be spending weeks of research/shopping/commissioning artisans so that their spellcasters can actually
use the spells they've suddenly learned.
