I want to use mana, used to fuel spells, as a sort of currency. Basically you pay for items not with a fiat currency but with your mana, which someone may later use to cast a spell. I don't have a specific world in mind for this yet, I'm mostly trying to figure out if a system could be viable at all.
A person can store on their person the equivalent of roughly 100$ worth of mana before they become uncomfortable. There are coins in various denominations that act as mana batteries that you can charge with your ambient mana. The governments of the world regulate the manufacture of these coins to prevent counterfeit coins that hold more/less mana, just like they had to prevent counterfeit gold coins.
The key catch is that everyone produces mana all the time, just by existing. This has an interesting affect on scarcity if that much mana is constantly being added into the system. Presumably mana is being spent for casting spells at roughly the same rate as mana as is being generated, and thus added to your economy, by all the folks living in a country, though some inflation or deflation may be possible.
Could this system result in a stable currency? I'm giving a good amount of free reign to answers to adjust how this world's magic system works, such as how much mana a human generates relative to the current available mana in circulation, what kind of magic mana is used for and thus how it adjusts to supply and demand, and if there are other sources of mana besides what humans produce. Given that leeway is it possible to create a stable mana economy?
If it is are there any peculiarities to such an economy vs the fiat currency of today? What does it mean to be rich or poor if your poor are able to generate currency by their mere existence?