Here's a perfect example of satisfactory solutions that are unsatisfactory, for me.
I started DMing with OD&D/BD&D/AD&D where buying anything but minor magic items, in my campaigns, was unheard of. In those days you made use of what you found. There was no magic item economy. And it worked for us.
We tried this approach in 3.x but it seemed that characters were more dependent on magic items, so our old method of play had to change if we wanted 3.x to work for us. I tried exactly what worked for Wicht, but it felt arbitrary and uneven to the group. I ended up using the 3E DMG guidelines and allowed just about any purchase under the limit for whatever settlement they were in. It was the best solution for us, but who knows, maybe it added to our issue?
I think that 3e codified things - that previously magic items were kind of arbitrary in their distribution.
If you look at published adventures for AD&D 1 and 2, there were a
lot more magic items than you were likely to see for 3e.
They also made CR a means to plop appropriate critters in place for a given level. CR gets a lot of flak, sometimes deservedly so, but it was better than what had come before, which was essentially
nothing.
I use
time as a limiting factor on magic items - you can buy them, up to the price limit, but other than pretty much standard potions you have to commission their manufacture. It will take the standard amount of time, so, buy now for the
next adventure, unless it is heading on toward winter. The pace of life slows down when the snow flies.
Unless it is The Iron Kingdoms, or
maybe Eberron, it is unlikely that a +2 flameburst broadsword is just sitting there on the shelf. (And in Iron Kingdoms it would be Glyph plates, the sword is just a chassis, you will have to wait for delivery, but we can order the parts for you today. We can sell you the +2 right away, and add the flameburst plate after it gets here, for a small extra fee...)
The Auld Grump, in Eberron go look at the Army/Navy Surplus store....