The Homemade flamethrower is the lowest-tier flamethrower.
How to build:
The things you will require are (in order):
The leafblower can be bought from the Hardware Store (require Director's Cut) for $1900.
The 40oz can be bought from 11-Seven for $90, or as loot from fighting the Eastside Mobster outside the Penthouse Suites.
Bring the items to Pyro Perry, who will then give the player the Homebrew Flamethrower and increased stats.