That depends entirely on how much of it you have.
Gunpowder varies from $15 - $20 American dollars for each pound.
Pretty much the rest of the world.
200 pesos
About 300 pounds
Gunpowder is bad because it could exert considerable damage to an enemy soldier and could to collateral damage to anyone who is by you because gunpowder quickly explodes into flames in an instant second causing sparks and insanity everywhere. Gunpowder explosives can go very far, up to 300 feet far from where your standing and almost 100 feet high. (Now that's high!!!) and there are a lot of other answer's, but that's all I know if you want more than you may look somewhere else but, I just gave you some of the important answer's.
It varies between types of loads, but on average, around 4 grams.
You need four sand and five gunpowder arranged like this: GSG SGS GSG
Depends on the size and duration of the war.
how much gun powder is sole each year
There is no specific collective noun for gunpowder, in which case, you use an appropriate noun suited to the situation a pound of gunpowder, a flask of gunpowder, a box of gunpowder, etc.
Gunpowder can be used to make a bomb. So unless you are licensed to be in possession of gunpowder, owning gunpowder is illegal.