Here’s some of the Grand Theft Auto: Vice City Cheats & Codes from IGN:
Parking Meter
Drive over parking meters to empty cash into the streets. It's free money!
Kill Your Buddies and Steal Their Cash
Once you move into the Starfish Island mansion in Grand Theft Auto: Vice City, you will always have a gaggle of goons hanging around your crib. Beat them senseless with any available weapon, and then grab the cash they drop. It isn't a lot, but it is easy money.
Rob the Bank
After you've completed the Malibu mission "The Job", you can rob El Banco Corrupto Grande for some easy money. Walk in and turn right up the stairs. This will earn you a four star wanted level. Walk into the manager's office to get 1/3 of the cash. The rest is in the room with the elevator, on the right side. Then jump off the balcony and run out. To shake the cops, you can turn left to the nearby Pay N' Spray. It's not much, but it's easy cash.
Easy Money on Stunt Boat Challenge
On the first Umberto Robina mission, get in the boat and then press TRIANGLE to step away from the wheel. Attack Umberto's henchman, who's in the boat with you, until he's on the floor of the boat. Now every time you kick him, you'll receive the Good Citizen award of $50. Wait until your cash stops adding before kicking him again or it won't count. (You do not have to wait until the Good Citizen bonus message leaves the screen, however.)
Easy Crazy Stunt Money
Get a bike and do a wheely. Keep the wheely going until you hit a lamp post or any other pole along the streets. If you crash at the correct angle, you should spin several times, thus gaining 40 to 100 dollars easily.
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