A Molotov Cocktail is a fuel bomb, cheap to make and easy to use. Simply fill a bottle with petrol and tie a petrol-soaked rag around the neck. A quick light and throw, and you've set something on fire.
In terms of Savage Worlds, it's as follows:
Range: 5/10/20 (small burst template); Damage: 2d10; Notes: roll d6 (5-6 catches subject on fire).