GTA III Shops
There are three different kinds of shops you can visit in Liberty City. They are Ammu-Nation, Pay and Spray and 8-Ball's Bomb Shop. Read the text below for information on each one.
This is where you can buy guns for a set price, just walk into the gun you want to buy and you will automatically get it, no ID required, simple. Some guns won't be available until certain missions are completed. There is an Ammu-nation in Portland and Staunton Island but not Shoreside Vale.
Pay and Spray
Aas long as your car is not a law enforcement or emergency vehicle (apart from the FBI Car) you can drice it in here and get it repaired and resprayed for $1000. Upon doing this your wanted level will disappear making this a good place to come to shake off the cops. If your car is completely undamaged, you can get your car resprayed for free. Just drive back in there until you get your desired colour. There is a Pay and Spray on each island.
8-Ball's Bomb Shop
This is where you can get a car rigged with a bomb for $1000. Just drive in and wait for it to be fitted, then press Circle to activate it. There is a bomb shop in each district however each one provides a different kind of bomb.
In Portland you will get ignition bombs. When you arm the bomb, the car will explode when the engine is next ignited. If you wait around for thieves to walk buy you can get out just before they open the door and watch them drive away and explode.
In Staunton Island you will get timer bombs. After arming the bomb it will explode after a few seconds so running is a good idea.
In Shoreside Vale you will get remote control bombs. After arming the bomb you can walk around anywhere and if you cycle through your weapons you will see a detonator. Make sure you are a safe distance away and press Circle to use it and watch it explode.