I'm not contuing my encounter balance article from last week, because I don't feel ready and have more questions than answers on the topic.

Now economy, that's fascinating! *Crickets in the background*

Ok, Ok, ... I kid.

It  might not be fascinating, but it is important. Because like in real life, gold, or Gil, or Yen, ... makes the game go round.
It is a reward , a reason to gind, and most of all the ultimate fungible currency and thus a wrench into the fine gears of balance.

Because somewhere there is a way to convert gold into anything the player needs, it is a way for the 
designer to give the player a small pat on the head ands say: good kid, here's some spending cash, spend it however you like.

But there are problems that lurks in most jRPG economies. 

I'm generalising, off course.

1. There is an infinite amount of money
2. The prices are weird
3. It is easily translatable into any type of power.

1. There is an infinite amount of money but no inflation.

The player is for al intents and purposes generating gold out of thin air. Even if you go the sellable loot route, that just adds an extra step. 

Even if we substract upkeep costs, like sleeping in an inn, potions, and damage to equipment ( if you do that in your game), every combat leaves the player richer then the one before it.
This usually escalates into the player having quite a sizable cash supply. 

Ahah! you think , I'll just let the player buy some gear in the next town, so he'll be back to being broke.
Now even if you calculated exactly how much encounters the player will have had, and the amount of gold he will have earned, most of the time it doesn't really work.

If the player has earned more than enough to buy all the upgrades, the problem isn't solved. The player still has too much gold.

When he has just enough to buy everything, why have the gold ? The player had no choice in anything. It becomes a chore : new village, new visit to the shops, incrementing the gear by one.

And a curious thing happens when he does not get enough gold. You would think : ooh , he'll have to choose what to prioritize, creating fun gameplay, but nope, 
he'll just go for a jog or 2 around the village and grind untill everybody has the new gear. 
Too many old games required and reinforced this behaviour, instilling in the player the feeling that if they did not have the best gear available in every slot, they might just as well not bother.
So eventually they still wind up with all of the gear, but by now they are overlevelled for the content, unless you accounted for this, but then it becomes a forced grind, antoher one of the crutches of the old jRPG's.

Personally I solve this by not having the gear grind, remember: my game has no straight upgrades in terms of weapons and armor, 
and just let gold be for consumables :potions, grenades,  ... 

Choosing between some healing potions or encounter ending grenades, maybe some repel powder feels like a choice, and players are less likely to grind for them, since they feel like extra's and optionals, in ways that the gear upgrades do not.

2. The prices are weird.

Because they do no result from any internal process, all prices in the game are arbitrary. There is no supply and demand, just the price that you'll pay.
No link between prices.

Why does the potion cost 50 GP and the antidote 25 ? Who knows.

Why does the potion that heals one character for a 100 HP cost as much as a visit to the inn ? 

Once you realise that all your prices are arbitrary anyway, you can start to see the big picture : Gold cost is a balancing mechanism anyway, so why not embrace it.

If gold can buy both permanent upgrades and temporary items, everybody will be buying the permanent upgrades, because that is what games have thaught us up to this point. Even if the sword+1 is 1000 gp and the potion is 10, we will still save for the sword +1.

3. Gold is power.

Gold earned is a second axis on the balance scale. A player that can somehow gain extraordinary amounts of gold without gaining levels means that you cannot just balance for what level the player will be. The amount of gold he had to spend is a  factor in his powerlevel.
Except it is way more eratical. 1000 GP on grenades is not the same amount of power 1000 gp on remedies represents. It is a weird axis of balance, unless you as a designer have a perfect idea of what the amount of gold in to power out is. 
But  even that does not solve the stockpile problem. You can't stockpile xp to spend it in one burst, but gold can be used in such a fashion.

The answer to this, in my mind, is to assign a basic unit of power to 1 gold piece ( or gil, or ...) and equate it to an equal MP cost, and prize all items according to that. This combined with a separate permanent/temporary upgrade currency split, should kind of solve this, I hope.

Another solution is incomparables. Is healing 50% HP the same as raising everybodies defence for 2 turns? Who knows, but it is a player choice.

Realy long story short, buying long and short term upgrades from the same pool will lead to weird results.