In Rift, there are five ways to acquire new armor and weapons. You can take it from the corpses of monsters you kill. You can run through dungeons, collecting new pieces from the tougher monsters and bosses. You can run from rift to rift, defeating the planar invaders and getting new gear from the rift rewards. You can craft it or purchase it from other players who craft gear. You can also use special currencies earned through various means to purchase new gear from special NPC merchants.
In existing tabletop RPGs, there are really only three ways to get gear – buying it from merchants, looting bodies, and finding it lying around in dungeons.
Many MMORPG loot mechanics won't work in a tabletop RPG because the gear just appears in the player's inventory when certain conditions are met. In a tabletop game, gear rarely just appears. I've touched on crafting in tabletop RPGs before, so this time around I'll focus on special currencies.
Rift's Currency for Planar Invasions
In games like Rift and World of Warcraft, you receive units of these currencies for achieving feats of excellence. For example, in Rift, you earn “planarite” and “sourcestone” for defeating planar invaders. Sourcestone is much rarer than planarite, each unit of its most common version being worth 50 planarite. It's only awarded for helping defeat special rift events like full invasions.
While there's only one version of planarite, there are multiple types of sourcestone, each being dropped by progressively more difficult planar invaders. In order to get the higher sourcestones, you must defeat higher-level invaders.
All of these can be traded in for impressive, rare gear. The best items cost a combination of sourcestone and planarite.
How to Deal with Special Currencies in Tabletop Games
In tabletop RPGs, by comparison, you're looking at a single currency – gold, credits, silver, whatever. In some games there are multiple types of currency but only one “track.” For example, in Dungeons & Dragons, you have copper, silver, electrum, gold, and platinum, but they're all just higher denominations of each other. This currency is accepted everywhere from all merchants.
To make sense, a unique currency needs to be widespread in use and creation, and to make sense in a setting, the powers-that-be need to allow that currency to exist alongside the official currency of the realm. That last part is historically difficult to come by, but in fictional worlds, we can gloss over that fact.
The best reason to include a currency like this is to gate powerful gear behind difficult tasks. It also provides a way to uniquely theme gear and work in factional alliances and reputation.
You could make up a large order dedicated to service to a particular god, for example. Instead of just being all priests or all paladins, this order could include a variety of skilled craftsmen who produce special gear. The craftsmen may only part with the gear in exchange for a special currency that only the order uses. Higher-ranking members of this order may be giving the PCs quests, and in gratitude for their help, rewards them with some of the order's currency.
This also offers role-playing opportunities, oddly enough. Possession of particular currencies could trigger interesting reactions from NPCs. Maybe they're associated with the producer of the currency. Maybe they're afraid of the producer. Maybe it's more complicated than that.
If it makes sense for your setting, try adding a special currency and unique rewards for that currency to your next adventure. It just might take your campaign in a very interesting direction.