Play the following missions and complete the indicated task or reach the specified level and you'll unlock the bonus.

Unlock Taxi Missions Bonus:
Steal a taxi and press the 'Up' button to begin the Taxi Driver missions. When you have dropped off 100 passengers the Bickle '76 cab will become unlocked.

Unlock Vigilante Mission Bonus:
To begin the Vigilante missions steal a Police car and press the 'Up' button. When you have reached level 12 you'll get 150 Max Armor points. Use the 'Spawn Rhino' code to easily accomplish this mission.

Unlock Ambulance Mission Bonus:
To begin the Ambulance missions steal an ambulance and press the 'Up' button, when you reach level 12 you'll unlock the Infinite Sprinting bonus.

Unlock Firefighter Mission Bonus:
To begin the Firefighter missions steal a fire truck and press the 'Up' button, when you reach level 12 you'll unlock the Fireproof bonus.

Unlock Food Delivery Mission Bonus:
When you are at the 'Noodle Punk' shop in Portland or the 'Well Stacked' Pizza shop in Staunton Island begin the Delivery missions and reach level 9 and your 'Maximum Health' will increase by 25 points.

Unlock Avenging Angels Mission Bonus:
When you have completed Avenging Angels mission in Portland the Super Angel bike which is bulletproof will become unlocked

Unlock Tourism Missions Bonus:
When you have completed the Tourism missions the Super Land Stalker will become unlocked.

Citizen Arrest Bonus:
Get an easy $50 when you see a cop chasing someone by catching that person and giving them a punch. If you punch the person more than once you'll end up in trouble with the cop when he's caught up.

Complete the following tasks to unlock the corresponding effects.

Unlock Infinite Ammo:
Beat the game 100%.

Get $10,000:
Complete ALL 26 unique jumps.

Unlock M60 Machine Gun:
Beat ALL Rampages.

Unlock Underwear Costume:
Complete 1 Unique Jump.

Unlock Cox Mascot Costume:
Beat SlashTV 2 times.

Unlock Dragon Jump Suit Costume:
Complete 'Crazy '69' mission.

Unlock 'King' Jumpsuit Costume:
Complete ALL Story mode missions.

Unlock Antonio Costume:
Complete the 'Making Toni' mission.

Unlock Avenging Angel's Costume:
Complete the 'Frighteners' mission.

Unlock Tuxedo Costume:
Complete 'A Date with Death' mission.

Unlock Sweats Costume:
Complete 'A Walk in the Park' mission.

Goodfella Costume:
Complete the 'Overdose of Trouble' mission.

Unlock Wise Guy Costume:
Complete 'Shoot the Messenger' mission.

Unlock Leone's Costume:
Drive to your house at the start of the game and walk into the clothes icon.

Unlock Extra 25 Max Health Points:
Complete Level 10 in 'Noodle Delivery' missions at Noodle Punk in Portland.

Unlock Upgraded Sanchez:
Complete ALL 10 courses in the 'Bump & Grinds' at the dirt bike course in Portland.

Unlock Extra 25 Max Health Points:
Complete Level 10 in 'Pizza Deliveriy' missions at Joe's Pizza in Staunton Island.

Unlock Hero Costume:
Beat Level 15 of the 'Avenging Angels' missions in Shoreside Vale.

Unlock Overalls Costume:
Complete 'The Portland Chainsaw Masquerade' mission.

Getting Busted Won't Cost Money:
Complete 'Avenging Angels' missions in Staunton Island.

Unlock 150 Max Armor Points:
Complete Level 12 in 'Vigilante' missions.

Unlock Fireproof Toni:
Complete Level 12 in Firefighter missions.

Unlock Infinite Sprint:
Complete Level 12 in Ambulance missions.

Unlock Bickle '76:
Drop off 100 Passengers in the Taxi

Unlock Bullet Proof PCJ 600:
In the 'Biker Heat' mission take Waynes Bike.

Unlock Micro SMG able to be purchased at Ammu-Nation:
Complete the 'Don in 60 seconds' mission.

Unlock Hellenbach GT:
Beat level 4 of 'Car Salesman' sidequest.

Generate $4000 at Capital Autos:
Beat Level 6 of 'Car Salesman' sidequest.

Generate 4x the Cash for Cars in the Scrapyard:
Complete the Scrapyard Motorcycle Challenge.

Generate a Boat Speeder at Portland Ferry Docks:
Beat the game 100%

Generate cash from 'Hogs & Cogs':
Sell 40 motorcycles in Belleville Park, Staunton Island.

Unlock Multiplayer Skins:
Complete the 'Driving Mr Leone' mission.

Unlock Rhino Tank in Ft. Staunton:
Complete the game 100%.

Unlock Super Angel Bike (Bulletproof) generated at Portland safe-house:
Completing 'Avenging Angels' missions in Portland

Unlock Super Land Stalker (Bulletproof) generated at Shoreside Vale safe-house:
Completing 'Tourism' missions.

Unlock Vehicles Take Double Damage:
Complete the game 100%.

Unlock PCJ:
Complete Love Media.

Unlock V8 Ghost:
Complete Love Media.

Complete the following tasks to unlock the corresponding effect.

Unlock Pistol at Safe House:
Find 10 Packages

Unlock shotgun at ALL Safe Houses:
Find 20 Packages

Generate a Armour at ALL Safe Houses:
Find 30 Packages

Generate a MP5 at ALL safe houses:
Find 40 Packages

Generate a Python at ALL safe houses:
Find 50 Packages

Generate a M4 at ALL Safe Houses:
Find 60 Packages

Generate a Sniper Rifle at ALL Safe Houses:
Find 70 Packages

Generate a Flamethrower at ALL Safe Houses:
Find 80 Packages

Generate a Rocket Launcher at ALL Safe Houses:
Find 90 Packages

Generate $50,000 at ALL Safe Houses:
Find 100 Packages

Never Wanted:
L1, L1, Triangle, R1, R1, X, Square, Circle

Money Cheat - $250,000:
L1, R1, Triangle, L1, R1, Circle, L1, R1

Spawn Trashmaster:
Triangle, Circle, Down, Triangle, Circle, Up, L1, L1

Random Ped Outfit:
L1, L1, Left, L1, L1, Right, Sqaure, Triangle

Spawn Rhino:
L1, L1, Left, L1, L1, Right, Triangle, Circle

Faster Clock:
L1, L1, Left, L1, L1, Right, Circle, X

Destroy All Cars:
L1, L1, Left, L1, L1, Right, X, Square

Peds Riot:
L1, L1, R1, L1, L1, R1, Left, Square

Peds Attack You:
L1, L1, R1, L1, L1, R1, UP, Triangle

Peds Have Weapons:
R1, R1, L1, R1, R1, L1, Right, Circle

Faster Gameplay:
R1, R1, L1, R1, R1, L1, Down, X

Slower Gameplay:
R1, Triangle, X, R1, Square, Circle, Left, Right

Perfect Traction:
L1, UP, LEFT, R1, Triangle, Circle, Down, X

Commit Suicide:
L1, Down, Left, R1, X, Circle, Up, Triangle

All Green Lights:
Triangle, Triangle, R1, Square, Square, L1, X, X

Aggressive Drivers:
Square, Square, R1, X, X, L1, Circle, Circle

Have Girls Follow You:
Down, Down, Down, Triangle, Triangle, Circle, L1, R1

Bobble Head World:
Down, Down, Down, Circle, Circle, X, L1, R1

Display Game Credits:
L1, R1, L1, R1, UP, Down, L1, R1

Upside Down Gameplay:
Down, Down, Down, X, X, Square, R1, L1

Upside Up Gameplay:
X, X, X, Down, Down, Right, L1, R1

Change Bike Tire Size:
Circle, Right, X, Up, Right, X, L1, Square

All Vehicles Chrome Plated:
Triangle, R1, L1, DOWN, DOWN, R1, R1, Triangle

Sunny Weather:
L1, L1, Circle, R1, R1, Square, Triangle, X

Clear Weather:
Up, Down, Circle, Up, Down, Square, L1, R1

Overcast Weather:
UP, DOWN, X, UP, DOWN, TRIANGLE, L1, R1

Rainy Weather
Up, Down, Square, Up, Down, Circle, L1, R1

Foggy Weather:
Up, Down, Triangle, Up, Down, X, L1, R1

Weapon set 1:
Up, Square, Square, Down, Left, Square, Square, Right

Weapon set 2:
Up, Circle, Circle, Down, Left, Circle, Circle, Right

Weapon set 3:
Up, X, X, Down, Left, X, X, Right

Cars Drive On Water
Circle, X, Down, Circle, X, Up, L1, L1

White Cars:
X, X, R1, Circle, Circle, L1, Triangle, Triangle

Black Cars:
Circle, Circle, R1, Triangle, Triangle, L1, Square, Square