What would they reasonably have? I have a teenager character who's background is that he's stinking rich. He lives in a big mansion, has expensive electronics and always carries a wad of cash with him. Game-wise, his resources is +4. In game, he still has to make the regular resource declarations, but we assume, for the unimportant stuff that he has what most rich teenagers would own. He doesn't have a lot of "disposible" income, because he's not 18 yet and he doesn't have access to all the cash.
They should have whatever weapons and tools that are part of their "trade". This could include a car, house, office etc...
For context, the character that started me thinking about this is the Protestant Ninja Inquisitor Assassin mentioned in a couple of other threads. She belongs to the Protestant branch of the Ordo Malleus, and she carries a bunch of countermeasures for some of the more common monsters (pure-iron shurikens, vials of holy water, garlic extract smoke bombs, etc,) and I was wondering how far this could realistically go.