Not just the supplies. You got to consider the amount of time that goes into making them, and the amount of money to sufficiently pay each affiliated member of that product. The time it takes to make a quality stick of dynamite might be worth about 50 gold, and to pay the people responsible for supplying the product, maybe another 50 gold each. Assuming Arastoph had a hand in it, the sticks could sell for well over 200, like you indicated.