GTA IV Cheats

Weapon Batch 1
(baseball bat, Grenades, M4, MP5, Desert Eagle, Rocket Launcher and a semiautomatic Sniper rifle)
(486)-555-0100 Cleaned the Mean Streets
Weapon Batch 2
(AK-47, Knife, Molotov Cocktail, 9mm, Rocket Launcher, Sniper rifle and Uzi) (486)-555-0150 Cleaned the Mean Streets
Full Health & Armor, Repair Vehicle (362)-555-0100
Refill Health, Armor & Ammo, Repair Vehicle (482)-555-0100
Randomly Change Weather & Time of Day (468)-555-0100.
Zero Wanted Level (267)-555-0100
Add 1 Wanted Star (267)-555-0150
Fix Broken-down Vehicle, will not fix the body Any Phone Number
Any time you're outside, bring up your cell phone and insert the following phone numbers to spawn the vehicles listed.
FIB Buffalo (Car) (227)-555-0100
Cognoscenti (Car) (227)-555-0142
Comet (Car) (227)-555-0175
Jetmax (Boat) (938)-555-0100
Annihilator (Helicopter) (359)-555-0100
Super GT (Car) (227)-555-0168
NRG 900 (Motorcycle) (625)-555-0100
Sanchez (Dirtbike) (625)-555-0150
Turismo (Car) (227)-555-0147

* Calling any other random number you find in the game from stores, posters, ect. will allow you to prank call that number.
* Note that out-running cops who try to stop you skipping islands when you are in a spawned Jetmax will NOT give you the Walk Free achievment, but you can get it later on in the same save file after you are killed.
* If you have completed all 30 of Stevie's Car theft missions, you can pawn any car you want for money like you did in his missions. If you pawn cars, you can make as much money as you want. The cars are worth about 1/3rd of what they were in his missions but you can do it over and over and over again.

Keep in mind that this table is presuming that the car is just spawned and has not taken any damage.
Vehicle Price
Cognoscenti $8,000
Comet $5,000
Super GT $11,000
NRG 900 $1,500
Sanchez $700
Turismo $10,500

The FIB Buffalo is the only unsellable spawn car. The Annihilator cannot fit in Stevie's garage and it is unlikely the Jetmax will either but it has not been proven.

Most cars have a low sell value, driving gently into a wall enough to scrape the pain will dramatically improve the value of certain cars, the SuperGT spawn and sold will get you $8,000, driving it slightly into the corner of the garage enough to ding it and then selling it will sell for the full retail value the $10,500 (i have had experiances where i have gotten 10,800.