One way to alter fantasy RPG campaigns is to alter the equipment available to PCs. In my post yesterday "Looking at the OD&D price list" I reproduced the equipment list with prices that is at the foundation of what everything costs in Fantasy RPG land , more certainly so in D&D and OSR games (the OD&D equipment list impacted games beyond D&D and it's clones). The use of the OD&D equipment list is loaded with assumptions of task, setting and role which define the campaigns that will follow.
Altering the equipment list will alter a campaign. Directed changes kept track of and maintained throughout play will have a lasting effect on how adventures unfold.
Breaking the mold with costume- One can break the mold that is set in place by adding to the equipment list with attire. The original equipment list doesn't include clothing for example (many later versions of the game do) and this provides room to costume the PCs and NPCs in the campaign. An equipment list with Frock Coats, Sleeve garters and Top-hats is going to look different then one with sandals and togas. With attention the DM of such a campaign is going to be able to communicate station and place of origin by how characters are garbed and this will carry over into PC play if costume matters.
Breaking the mold with prestige purchases- One can break the mold by introducing goods into the standard equipment list that are clearly luxuries that bring status to the purchaser and those at the table. The items that are considered prestigious will help set the tone for the campaign that follows. Silver arrows and silver daggers aren't opulent enough then why not silver swords? Exotic furs and foreign materials can declare one to be of high station and wealth and this can alter NPC reaction (He must be a king he's not covered in...).
Breaking the mold with availability- where and when goods can be purchased will impact a campaign. Many a player assumes the whole equipment list or a substantial subset of it is always available breaking this will alter play. If certain goods can only be found in specific places adventures can flow related to acquiring those goods alone. This can also lead to the issue of the shop-quest where entire sessions seem to get spent on shopping so it should be used as fits the pace and tone of a campaign. Goods can be tied to the size of a community. It is logical that some regions will produce some goods at vastly different purchase points. Supply and demand is an easy to understand economic force that can be represented in a campaign. Availability can also be altered by the locations and skills of craftsmen.
the following is and example of the availability based on he presence of craftsmen: In a my current campaign a player wanted a wyvern hide fashioned into a suit of Hide Armor, I as DM agreed it was possible and gave him the green light on getting it done. the limit on availability in this case wasn't on materials the player clearly had the hide but on the workmanship. With a little effort the player was able to have his PC find out what armorer in the surrounding realm was able to fashion the hide into armor and then he had to travel there and get access to the castle where the armorer was employed to seek a private meeting with the armorer to contract the work on the armor.
Availability of goods and services is also based on cultural and economic assumptions that need not be present within a campaign (or at least not ever-present). A campaign that simply doesn't' have a inns or taverns as common-place features will alter the flow of a campaign. Eateries and sleeping places can be tied to clan or cadre and outsiders may simply be unwelcome, over charged or only allowed limited access during holiday periods. This ties access to a commonly used service to a PC relations to NPCs and is sure to differentiate a campaign.
In one campaign I dm'd there were simply no formal Taverns and no Inns outside of major settlements. Drinking establishments were infrequent and varied based on what home had a batch of brew available for sale, a nights rest had to be sought out and bargained for in each village.
Breaking the mold by changing the prices. One sure way to make the players notice the differences in a price list is to alter the prices. An equipment list can be priced with a closer eye to actual production costs (which requires a bit of work on the DM's part). Prices can be set for purely gamist reasons, weapons that do more damage will cast more, noticeably more real world economics matter little to an adventurer who wants to purchase a Jotun Axe fro 200 g.p. because it does 1d12 damage instead of a Dwarven Waraxe that does 1d10 for but 100 g.p.. Gamist pricing can be front loaded to make most goods available to a starting party or they can be built to give players equipment purchasing goals for their PCs as they adventure. Plate mail that is 60 gp has a different role in a campaign from a suit that costs 400 gp or one that costs 1,000 gp.
Breaking the mold with expanded equipment capability. Including equipment that does something different in a campaign or adds extra functionality onto items in the commonly available equipment list will alter how a campaign plays. If there are pistols and muskets on the equipment list there certainly something different going on. Acid vials and smoke bombs are other examples of more exotic goods that will alter the pace and style of play if they are commonly available for the coin they demand. Expanded equipment availability alters the range of tactics in play and implies differences in the society as well.
Breaking the mold by introducing new sub-rules that relate to equipment. Altering the in game role of equipment and how that is expressed in play can have an impact on a campaign. Some goods will be in higher demand others will vanish or be odd purchases for adventurers. Will shields have special rules in combat, will presence or type of helmet matter in play? Which boots are better for sneaking? If clothing makes the man what impact on charisma does a Lucarddian Ruff collar have? How many drinks can my dwarf quaff before passing out? There's a lot of room here for campaign influencing detail. Too much cumbersome detail or seldom experienced sub-systems and they will be forgotten and shoved to the side
Equipment is a major factor for play in fantasy RPG's and it's a chance to express the campaign settign on the players record sheets,some place they actually look at on occasion. shaping the equipment and how it relates to play will help a campaign break the mold.