Funnily enough, I was thinking about this today. I've also played a lot of World of Darkness games and just can't be bothered with counting the brass pennies, so am intending to bring a resource mechanic into the game.
The way I do so will be like this:
At creation, players choose which class/tier they are (in collaboration with the GM, and this obviously will depend on the career they draw/pick).
This is most likely to be brass, but could be silver and I wouldn't totally rule out gold.
I will give each player 3 distinct resource tracks, rated from one to five. With a ‘1’ being 'absolutely skint' and a ‘5’ being 'can buy any product or service in this tier without a second thought'. The player then spends creation points on wealth as normal, and this will mainly drive the starting position of their tier resource.
So a brass tier character who puts 2 or 3 points into wealth will start at 4 or 5 on the brass track, and probably at a 2 on the silver track. I don't need an exact formula, as these resource trackers will change during game play. A gold tier player spending only 1 creation point would start at a 1 or 2 on the gold tracker, probably a 3 on the silver tracker and probably a 2 on the brass tracker.
Spending the maximum creation points will never give anyone a ‘5’ on all 3 tracks. The richest brass tier character may just have single point on the gold track. The richest gold tier character will not have a full brass tracker simply because they wouldn't carry (or likely have easy access to) that quantity of brass coins. However, they'd be able to eat out at fancy restaurants very easily.
As the game progresses, and depending on work, loot, rewards, etc, the players will adjust their wealth tracks, perhaps making 'wealth management' rolls every now and again, to see if they are spending more than they're taking in (or even making more money). I'm not sure exactly what this roll will consist of yet, and could be different things at different times. But it will take into account haggling, budgeting, choices made in restaurants, or between coaching inns, etc. I may let them make haggling rolls etc during the game, but rather than have players cross off the coins they’re spending just bear the results in mind for the next time there is some ‘down time’, at which point I’ll adjust their wealth tracks up or down depending on how they’ve been doing.
The last point to mention is that I think character creation points should remain valuable in the long run. It’s not fair if a player spends points on wealth and is robbed 5 minutes into the game, whereas the player who spent all their points on stats will still be fine.
So, my characters’ wealth ‘stat’ will influence how well they are able to manage their money. A character with zero points in wealth will find it impossible to stay rich for long (without spending exp. on improving their wealth stat): they will gamble the money away, mislay it, get ripped off, spend it on baubles, etc. They won’t know how to handle that amount of money, won’t know the value of expensive objects, and likely won’t even be able to count using such large numbers.
Conversely, a character who spends full creation points on wealth, and who is robbed blind, will quickly find themselves in the money again once they have the opportunity to make/acquire some, driving hard bargains, knowing when to flash the money around to create business opportunities, etc.