I'm developing the design outline as well as the C# loot method(s) for Sublime(working title). At first I was planning to shy away from the simple 10 Plat (C-Note)=1000 gold (dollar)=10000 silver, etc hierarchy. To add slightly more depth I was planning to use different classes of currency, with most in-game buyables requiring a mix of several currency types. For example an low level encounter might yield: 18 ergs (basic measure of energy) 23 Info (basic measure of data) 13 viscera (basic measure of bio-matter) A desirable in-game item from an NPC merchant might be: { Moore's Law Generator Provides your research a 200% boost while equipped. Cost: 13 viscera 1939 Info } The questions are, Have you ever implemented multiple currencies? How would you think the complication and depth added by multiple currencies impact the player. Thanks,

From what I understand, the hierarchy was created to circumvent big numbers on paper (and encumbrance limits) and later to more nicely handle rollover issues on fixed size numbers.

What is the design motivation for multiple currencies? I can't think of one off hand that might not be better implemented with a different stick/carrot.

in my opinion you are blurring the line between money and crafting resources. unless dealing with multiple countries I wouldn't even think of different types of currencies for the same thing.

I'm glad I asked the questions, good feedback especially the analogy on the grind.

I should explain my motivation for different types related to my draft on the game mechanic.

One aspect is for different encounters to have different currency 'drops'
Events involving machines/computers/networks yield tend to yield Info whereas an encounter with a living NPC would yield Viscera and some Info, etc. This also follows along what territory a PC is exploring

Different professions would be more efficient at handling and converting certain currencies, ie Lab Scientist is more 'attuned' to processing/spending Info whereas viscera is better for a Gang rogue.

There are different trade aspects involving the currency in the MMO aspect.

From the comments I'm feeling that multiple currencies might be a detriment to gameplay, I'll continue to muck around. It's important thing to nail down now as it affects a lot of the gameplay.

Call them resources, not currency, because that's what energy, data and "bio-matter" are. Merchants asking for a composite price like in your example are completely abnormal; there is barter with whatever is at hand and trade with generic money, and your merchant would be doing both at the same time.
A merchant willing to accept any bio-matter and any information as payment would need to be able to trade them away promptly, which is unlikely; but if such markets for information, energy etc. exist the merchant should be able to accept any combination of your non-currencies, which would have market-driven exchange rates.
A party that needs a specific amount of bio-matter and information, on the other hand, is not a merchant trying to make a profit, but someone with a specific purpose that presumably needs specific data and materials, not generic resources.

On the other hand different people in a fantasy world could use different goods for trade, blurring the line between barter and money.
Nomad tribes could price everything in sheep; P2P fanatics in copyrighted songs (with several grades according to rarity); demons in damned souls; spacefarers in standardized exotic fuel; etc.
Such systems could merely add colour to the game setting, make use of "money" as interesting "items" (e.g. arranging transportation for a payment of 200 sheep) or control player wealth (e.g. barbarians wouldn't be interested in a character's stash of 200K rare songs on little memory chips).