# How would one create a bag of coin-changing?

I was chatting with a friend about Dungeons and Dragons, and he had mentioned that in 4th edition, there is an item that converts coins to different denominations. In the campaign that I am running, the players are carrying around quite a bit of copper and silver, and it would be useful for such an item to exist.

I was trying to price out such an item using the Bag of Holding as an example, but it only lead to further confusion.

From what I could gather from the item creation rules, the cost should be

(Spell Level) * (Caster Level) * 2000gp * (Factor based on spell duration)


...For being a use-activated / continuous item. The closest spells I could find were Major Creation and Fabricate, but even optimistically that would put the cost at something like 90000gp!

How would one create a bag of coin-changing, and how much would it cost?

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Are you talking about transmuting copper coins into other denominations one for one? Or simply making something that can exchange currency at the standard market rate? I think the 4e item you're referring to is Pouch of Platinum and it doesn't create any value. – pian0 Mar 17 '11 at 11:50
@pian0, there's also the Fluid Funds ritual, which can convert coins (or nonmagical, non-equipment items) into gold pieces. Fluid Funds requires the Mark of Warding Dragonmark feat, though. (And, like the Pouch of Platinum, it doesn't create value, unless you count avoiding the 20-50% loss on sale of items as creating value.) – Brian S Apr 15 '14 at 13:36
I wrote up a custom 0-level spell for my D&D 3.5 campaign that converted coinage in the 10:1 ratio (adding no market value). If you grant that coins really do follow the 10:1 ratio, you almost have to assume such magic exists to maintain that ratio. – Dane Apr 15 '14 at 17:59

The main difficulty you're having in using the formula is that there is no existing spell that models the effect you want. Both Major Creation and Fabricate are dramatically more powerful than the effect you want in that they can create almost anything. Placing the limitation of converting coins of one type into another type of precisely equal value is a huge limiting factor.

For my part, I would put "convert currency" at a pretty low spell level (0 - 2). This is because I don't typically play campaigns where encumbrance or money changing are relevant... If either of these mechanics ARE relevant to your campaign, adjust accordingly.

Based on that, you'd get a cost more like:

1 * 1 * 2000gp * 2 (bags have no space limitation) = 4,000gp


Which is still probably too expensive to be practical (why not just get another bag of holding to handle the extra coins?)

For a zeroeth level spell:

.5 * 1 * 2000gp * 2 = 2,000gp


... Maybe.

The other way to approach it is fiat: In order to be relevant, the item has to have a cost below a type I bag of holding. Therefore the price has to be somewhere in the 1,000gp to 2,000gp range. So it is.

The problem here is that the formula is balanced on existing, challenge-relevant spell effects. It works much better for an amulet of protection from evil than it does for a minor utility spell. This is why, for example, the Feather Tokens don't have the extremely high costs that come from creating something for nothing.

Why is the bag of holding so inexpensive compared to the formula?
- NT3RP

Because the bag of holding doesn't really make characters more powerful, but it does make them more convenient to play.

A character with a bag of holding won't defeat many more challenges than one without. If it was more expensive, players would have to spend a lot more time on mundane tasks, like getting the loot out of the dungeon (which can be interesting, but not if you have to do it every week).

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Don't forget about the artifact that can turn 1 gold coin into 25 gold coins daily. That emulates the multiplication aspect quite well, even if another spell doesn't emulate the description exactly. – Sandwich Jul 26 '14 at 2:12

You should go off of extradimensional-space spells like Rope Trick. Just say that in this case, the extradimensional pocket can be accessed by bankers in Sigil (or somesuch). So you have to wait a few minutes for them to do the transfer, and maybe they'll take a small fee.

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+1 for a suggestiion that explores the mechanism by which such a magic item would function, doesn't crash the precious metals market, provides potential plot hooks, and which is a Planescape reference. Bravo! – GMJoe Mar 15 '12 at 5:08
I'm not sure you can open your own portals in Sigil. – Zachiel Mar 1 '13 at 14:51
@Zachiel There's ways around that. For instance, the bag's portal might link to a secure vault in Arcadia that's conveniently close to one of the pre-existing portals to the city of doors. – GMJoe Apr 15 '14 at 3:50

The 4e item you're refering to is most likely the Pouch of Platinum[DDI]:

Property: Normal gemstones and coins of any denomination placed into the pouch are converted to an equal value of platinum pieces. Coins or gems that cannot be evenly converted to platinum pieces are unaffected.

Do you really need to follow the exact item creation rules (as in, CL, spells known, feats, etc.) or was it sufficient if you knew the relative powerlevel of the item to simply say "it costs 1000gp" or something like that? It's been a long time since I dealt with 3e item creation and I'm a bit rusty with it, but I'll try to figure something out.

Another idea: what books do you have? I only have access to the SRD right now but perhaps an appropriate item or spell already exists in some supplement.

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I have most of the 3.5 books, excluding campaign settings; I don't recall anything like that, but I could take another look. I suppose it's not really a question of exact price, but relative price: How do I know if it's too expensive / not expensive enough? – NT3RP Mar 7 '11 at 18:09
Also, I suppose a follow-up question would be: why is the bag of holding so inexpensive in comparison? – NT3RP Mar 7 '11 at 18:12
@Nicholas T, the Pouch of Platinum is a 4E item, the one you were chatting with your friend about. – Snowbody Jun 29 '11 at 21:35
Y'know, it strikes me that having even one of these in a setting would gradually alter the rarity value of the metals used in coinage. Ah! I guess they must be balanced out by the 'Sacks of Silver' and 'Caskets of Copper' that NPCs use to make change. – GMJoe Mar 15 '12 at 5:06
That link doesn't work for me, this one does wizards.com/dndinsider/compendium/item.aspx?id=2086, also, you might want to specifically mention that it costs 1,000 in 4e, which may or may not be helpful. – Not a Pumpkin Apr 15 '14 at 3:40

You could base it on the Tech 2 items in the MMORPG Eve Online.

Components needed:
Bag of Holding
3 gold coins of differing type (if in the real world say a dollar, a pound, and a Euro)
A piece of silver chain (links = linking the coinage together)

Resulting item would provide the ability to put coins of one country and get out the coin of the current country (or store your coins in it and they always come out in the local currency), with the restriction that once the bag of holding is changed then it can only hold coins (unlimited number though) and anything in the bag when the spell is cast are lost (the interdimensional space inside was changed so anything in the original is now lost). I would place it as maybe a level 7-9 spell.

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I'd treat it as a variant spell of Transmute Metal to Wood. Up it a level or two.

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Just list it as having a faint or moderate transmutation aura, and just requires the casting of any 2nd (or 3rd) transmutation spell during the crafting. An easy way to handle crafting one, without having to design new spells, or use ones that are unreasonably high.

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What I would do is create a level 0-2 spell called limited trransmutation. It basically just changes a amount of coins into the economic equivalent of a desired coin. Don't just give it to the players though, make them go on a side quest to a greedy wizard's tower or something. Make them work for the spell.

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