[Lostangel]

Here is how I would reduce money in the game...

Item degredation - Each use has a chance of reducing the effectiveness of an item (ranged, melee or armor) when used in an attack (not when used to defend).

Cash transfer fees - A fee on transfers over a certain amount. Higher limits for donators and to gangs. Limits on the amount transferred per day.

Item transfer fees - based on the cost of the item

Housing downgrade fee - If you sell your house, pay a fee

Edit: Thought of another one... Tax on the house you have.