Not knowing which direction you wanting to go in. I will start with a little premise work.
Character costs:
Each character costs should be based upon various factors. What class they are, will effect the costs incurred by that character. (As you seem to be heading in a more character class direction.)
Also the introduction of a set of housing, for rent will incur a sort of upkeep. This recommend a 10 - 30% of income range. This also depends upon, how you want to approach the storage issue.
Some basic ideas:
Hovel (For newly joined players)
5% income, storage max 50 separate items. (No rare storage access.)
Inn (Skill lvl 10 -20)
10% income, storage max 75 separate items. (No rare storage access.)
And so on. The more lavish the location, the more income must be spent in order to keep it. You could include things like: A mansion with stables for your own horses. Or even a castle. Depending upon which direction you wish to take the game.
Income:
Not knowing, how or even if you want any rare items in the game. Or even how your going to handle them. Please let me know.
You could have different scales of rarity, for example. Thus there worth in the game, is based upon how rare that resource is.
For example:
Abundant: An almost in endless supply, such as flowers.
Plenty: A lot of this resource, such as rabbits.
Typical: The average resource, such as iron ore.
Scarce: Hard to find resources, such as silver or gold ore.
Rare: Very hard to find resources, such as hydro ore.
Unique: Extremely hard to find resources, such as binding stones.
You have the option, now how to approach the rarity issue. You wish to follow the EL model? Combination of: long walks, PK areas and luck?
Or a supply regulated approach? What do I mean by that?!
Well for example, one approach might be:
Abundant:
Any player can harvest this resource at any time.
Plenty:
A limit amount within the game. Say 10,000 of this item can be harvested per game day. (This could be per map or area or each location for that resource.)
[This allows options for breding in the creature area, each creature can bred at a certain level for example.]
Typical:
A limited amount as above. Or in relation to say ore's in caves. There could be a NPC outside, who takes voluntary donations on the 'upkeep' of the mine. If the players choose to make regular donations, then the mine will suffer less wall collapses and therefore players take less damage.
If players do not choose to make regular donations. Then there will be more wall collapses and more damage for players. With a possible end result that the mine just caves in. There the players can not use that resource any more. Perhaps, unless they spend 'X' amount of time, digging all the rock out and repairing the damage inside the mine. (Wooden struts and so on.)
Scare:
A limited amount as above. With the NPC always charging a fixed amount for entrance. Perhaps in the case of silver and gold mines. There owned by the local Baron or King and the player has to bribe the guards, in order to gain entry.
Rare:
As above. On a PK map or high level monsters wandering around. Etc...
Unique:
Rather than luck, you could use a math system. Say for example a 1,000 to 1. So 1,000 Abundant items to create 1 Plenty item. Then 1,000 Plenty items to create 1 Typical item. I know this will not apply to most of the goods or items currently set up in EL terms. But it gives you an alternative to the lucky based system. You could say 1,000 rare items to create a unique item, this is just an example. Of course.
Basic Item worth:
Using the basic system above, with a proposal of a basic unit cost. You can calculate a base cost for all base resources.
Base upon: 1emu = 1gc (for example)
A: 1 P:2 T:4 S:8 R:16 U:32
(Dependant upon the scaling system you wish to use, if any.)
Thus, if you already know the basic costs of all base resources. Then it is much easier to balance costs and creature/monster drops in accordance to the 'target' demands. Hence depended upon hours played in the game, you can for see income versus costs.