$50,000:
Press [Caps Lock], then type i love hanson at the Lieutenant screen to place
$50,000 in the safe, if the current amount is less than that.
Extra money for all gangs:
Press D + A + R + T at the Lieutenant's section of the gang organizer to
give $3,000 to all gangs.
Free items:
Go to the Lieutenant's page of the Gang Organizer, open the Cars menu, and go
to the "Black Market". Instead of clicking on the car you want and waiting
for the money clip to appear, quickly drag the car of your choice from the
"Black Market" page to the picture of it on the Lieutenant's side. If this
was done fast enough, the item will be yours, with no money being subtracted.
This can also be done with guns, but does not work with recruited hoods.
Note: Try this first without having enough money for the object, as it takes
some practice. After each time this trick is used (whether successful or
not), exit the "Black Market" and return.
Sites: