IIRC Greyhawk used to have price multipliers in the Gazeteer entries. They changed prices from the PHB default for areas that were afflicted by scarcity and/or glut. You'd get something like:
Rel Astra
Price Multiplier: 100%, {local speciality} 90%
or, for an area under immediate threat of war:
Nyrond
Price Multiplier: 150% (200% for weapons and armour)
I imagine it would be easy enough to include this in a homebrew setting if you wanted to add a quick and simple element of Dungeons & Derivatives. It also adds a little local colour, the impression that the world has variation, and that you don't just go to a price-standardised Adventurer's Wal*Mart for your kit.
The Dorf Fortress crafting skill and item price system might be of interest in this respect too. It has more granularity than the D&D normal > masterwork > magic system, but is probably a bit too number-crunchy for those of us with "Money is used to get ale and wenches; all else is sheer lunacy!" tastes.
PS: the D&D economic system by the RAW makes Adam Smith rise from his grave screaming in agonised rage. WOTC staffers fail Econ 101 FOREVER!