Hello!

Thank you for that game me and my party are currently playing.

I have question about gold, why there is almost no mechanics about gold and treasure, but we have Coins Fellowship with Dungeoneers sub class? We are planning exactly this type of Fellowship and every player of mine explain motivation of his adventure like greed of money. 

Do you think that money isn't important in your game?

Yes, there is resources, but you can restock it everywhere.

Currently we are not using any mechanics for gold, but if or when it becomes important I think that I will add additional counter for gold(few, enough and etc), what do you think about it?

Hello Ngoroth :)

Happy to hear you're enjoying the game :D

The design reason is that FW doesn't want to give importance (in terms of time, effort, mental space, etc) to the everyday logistics of "money".
PCs are always assume to have as much "buying power" as the fictional positioning make it reasonable for them to have.
Thus, Players don't track coins.

Moreover, any PC could just start the game being noble, rich, or both, and thus be entitled to have any level of resources and luxury that would make sense. The One Golden Rule to help basic human communication are there to ensure gameplay stays at a level that makes sense and satisfies everyone.

Therefore, the COINS fellowship is never chosen because the PLAYERS (not their Protagonists) want to accrue fictional riches.
That fellowship exists to allow Players to play Protagonists that go forth adventuring as a "profession". Money is one of the main drivers for those characters, but the game is disinterested in engaging with it. It's just a motivator. The real object is immaterial.

Example...

An NPC wants to hire the Coins, but they are too poor to pay "the usual" fee the Coins would ask to a normal client. What do they do?
The game is interested in posing this question, and in seeing what kind of answer the PCs offer.

An NPC wants to hire the Coins, but someone in the fellowship tries to barter for a higher price. "You pay us more or we don't have a deal!"
This can totally happen, and will probably translate into interesting and meaningful reactions from the NPC/World, and probably trigger moves from the PCs, producing engaging play.
How much is "more" ?
Is it a lot or a little?
These questions are immaterial, and can freely answered on the spot:
- We are asking for exactly 75 more Frilly Brilly Tokens, not one less! :P
- Wow, that's a lot for a normal person! But this is a rich merchant, they will sweat but could probably pay without real problems.

More interesting questions would then be... Is it worth insisting on it if the NPC makes problems? Can we then trust them to pay up what was promised? Why even ask for more in the first place? What does this behaviour say about the PCs individually? And as a known fellowship? Do you have a goal for the money you accumulate? Does then adventuring pay well or are you just scraping by? If it's just a normal 9-to-5 job for you, is it worth risking your life for? What about now? And now? Etc...

As you see, actual amounts of money are of very little interest for the core elements of FW. Money might be important for the PCs, and they have it and use it off screen. Instead, for the Players money is just an excuse for adventuring.

That said, nothing prevents you from tracking SOME SORT of monetary resource, or the overall level of luxury and life-style the PCs have. Just use the rules in the Equipment & Supplies chapter :)

The loot from an adventure might be jotted down as a single Tag, affecting the fiction because... it is heavy? cumbersome? is it represented by a single chest or a few bags? is it flashy and hard to conceal? is anyone after it? will it be lost during a particularly problematic and hectic scene? does it make you a target for bandits and thieves? what happens when the PCs meet a poor village in dire need of financial help? what will they do with the treasure they are carrying then? what will the desperate villagers do if they find out that salvation is at hand, but being withheld?

This is the important stuff, in FW :)
Then sure, the loot Tag could also grant Advantage on Restock moves as the PCs spend bits of it... IF the PCs are somewhere they can spend their loot in. Is it gold? What is gold worth in the middle of the desert? Is it ancient books and paintings? What are they worth among savages, or among a civilization that doesn't understand them, or that has grown beyond them?
And of course it could lose worth (just rewrite the Tag accordingly) if the PCs spend too much of it, or it gets damaged by the environment, or in combat. Is it worth holding on to it (and all its implied drawbacks) until the ideal destination to sell it for profit? What if the recipient client makes problems because the loot is not as pristine as they expected? Etc...

Once the loot gets offloaded somewhere safe and somehow converted into resources it might simply turn into normal supplies for everyone, or special unique objects, or why not a special "Supplies" track, separate from the normal one, to specifically represent how much money the PCs have? This works best if you play at a level where that would also GET USED for something... like... hiring henchmen, bribing nobles, maintaining some sort of estate, trying to apply political pressure, running a real business, etc.
If you are really just going to play the classic adventuring party out for the next bag of gold coins, this is better left out, as it adds near-useless elements that will only distract and get in the way of what people really want to do :P

Of course none of this is set in stone :)

Play might start one way, then evolve in some other direction. Maybe for your specific group and campaign, tracking money in more detail makes sense. FW offers you a bunch of tools you can easily scale up and down in detail and complexity.
My personal advice is always to start on the lighter side, relying heavily on pure fiction and nothing more (Tags, Agents, descriptions, fictional positioning). Then try adding small and simple bits of mechanics if/when there is a specific thing you want to be more central to the game you play. The final chapter has a few words of advice on how to hack and modify FW to your needs and desires... you could end up crafting a "harm" system for financial warfare between rival city guilds, or even nations in cold war ;-)

Let me know if these comments are of any help, and if you have any more questions :)