GTA Sanandreas Hints

Pimping missions bonus:
Steal the pimp convertible in the car wash parking lot near the Pay N' Spray and
start the pimping missions. Successfully complete level 10 of the pimping missions
to get money from prostitutes instead of paying them.

Quarry missions bonus:
Successfully complete level 7 of the Quarry missions to get the Hunter Quarry asset
and Quarry Mission time-trials.

Taxi missions bonus:
Steal a taxi and start the taxi missions. After a total of 50 successful fares,
you will unlock hydraulics and nitrous on all taxi-class vehicles. After using
nitrous, you must wait awhile between shots. However, that time decreases as your
driving skill increases.

Truck missions bonus:
Steal a truck and start the truck missions. Successfully complete level 8 of the
trucking missions to unlock RS Haul as a property.

Valet Parking missions bonus:
Successfully complete level 5 of the Valet Parking missions in downtown San Fierro
to get the San Fierro Valet Parking as an asset property.

Vigilante missions bonus:
Steal any policy vehicle and start the vigilante missions. Successfully complete
level 12 of the vigilante missions to get an armor limit of 150.