Basic Trope: The further you get in a Video Game, the more you have to pay for items, regardless of any factors like supply, demand and the fact that you're trying to save the world.
Straight: Albert and his friends travel the world; by 'coincidence', in each new village, town or city they visit, everything is more expensive, from the Inn to the admittedly better selection of weapons, armor, and other supplies.
Exaggerated: Every inn doubles in price as you continue through the game, even though you start in the largest, fanciest, most expensive city in the world and end up in a straw hovel. A new car in the metropolis costs less than a stay at the hotel in Pudonk.
Downplayed: Each new area has realistically priced Inns, as well as items, but the characters are traveling to more expensive or deadly places, so it's understandable why the Inns would get more expensive.
As the crisis builds, resources are getting scarcer and fewer people are leaving their homes to do business, so prices go up by necessity.
The shopkeepers have already given enough charity to would-be heroes, who either failed to save the day or simply ran off to resell the items at an inflated rate. Not only does this give them reason not to trust you, it also forces them to jack up their prices.
The further the hero's go in the quest, the rarer the items they need/can use are. As such, prices go up.
The further you get in the game the cheaper the items get.
Subverted: Once the world begins to end, the merchants near the final dungeon start giving their items away virtually for free so the heroes can protect them.
Double Subverted: ...but after the boss is defeated they ramp up their prices even higher to make back what they lost.
It turns out the world's entire economy is based on how far the heroes are from their hometown.
Adam Smith himself has met the heroes before and winds up hating them for one reason or another, and inspired this economic system in the first place as payback.
Zig Zagged: Most shops in the game have items in stock based on what a store in that sort of place (be it a podunk village, merchant's hub or capital city) would logically keep on hand. The inn prices are similarly skewed, with out of the way backwoods inns always being cheap while inns located in the big cities are more expensive. However, there are a couple of out-of-the-way inns that still happen to lay in strategic places that charge through the nose for their services, and there is a general trend for more expensive weapons and armor to be found in later areas... but these latter cases are generally within the empire themselves.
The game has a realistic economy, with all the resultant ups and downs that entails.
You get a "haggle" skill or are able to barter with older equipment.
All non-plot related items are available in various progressively richer commercial districts that can all be accessed throughout the game.
Enforced: It may not be realistic, but setting the game world up in this manner allows players fairly easy access to weapons, armor and the like that's on par with their current level as they progress.
Lampshaded: "Yes, my prices make no sense. But where else are you gonna get this stuff?"
"If I set my prices ridiculously high then I can make a killing, since no one else sells this stuff!"
"See here, young human. I have three wives and about nine or ten cubs to support. If I just gave these Medkits to every group of six people saying that they're heroes who have to save the world, we would starve. And there's fewer and fewer Medkits every day. That is how I 'get off', as you put it, charging a hundred Quid for a box of band-aids and a jar of rubbing alcohol. And that gilded pistol's not for sale, it was my grandsire's."
Exploited: Albert goes to a town that is controlled by and built around the big bad. Albert realizes it's late in the game, so he spends lots of money on the more expensive services to convince the other shops to switch, effective causing an economical crash because the services get to specialized for the heroes.
Defied: "Setting my prices ridiculously high for four people when I live in the biggest city in the country? Forget that".
Discussed: "Ever seem like prices get higher the further we go from home?"
Conversed: "Why does everything cost more for these people as the game goes on? Is the economy slowly collapsing?"
Albert and his friends get to the point where they simply can't afford the expensive equipment and services anymore, and wind up dying horribly.
Alternately, the impending End of the World as We Know It has caused the currency to become completely devalued, resulting in obscene hyperinflation, and the shopkeepers are so paralyzed by fear of their impending doom that they focus entirely on the one thing they know how to do: hawking their wares at obscenely marked-up prices.
Reconstructed: Albert and his friends notice the trend and become very good at managing their resources and budgeting, allowing them to survive in this crazy messed-up economy.
Played For Laughs: Every time the heroes reach a new town they have one gold piece too few to actually buy anything.
Played For Drama: A major part of the game is how all the shopkeepers are abusing their monopolies on certain goods to make money illegally. It turns out that the merchants deliberately keep a large part of the country in poverty and unable to buy basic food because they want to make more money off the heroes.
Plot Foundation: The hero's hometown has cheap, plentiful goods, as it is free of the Merchant's Guild's massive markup. The work is about how the hero becomes a smuggler to get these cheap goodies to everybody for a reasonable price.