Bank Card's - wouldn't it be good to have the option to apply/buy a bank card where you can carry money round without the fear of being robbed for cash. you can make purchases from it with a !0% charge? of course your card can be took from you but any transactions made will show up and the game tag of the player will show and can then be reported to the police.
owning a country house - you can plant illegal drugs on your land
business partners - you can invest in a business with a friend, half the costs half the profits
Buying and selling vehicles - you can buy second hand or impounded cars (used in heists or drug carrying seized by the police and sold to a wheeler dealer in turn he can make a small profit when selling. or damaged cars brought to a scrap yard in turn for money where the car can be scrapped for resources or fixed up and sold off
any other ideas?