score:6
From Sketch of the Mode of Manufacturing Gunpowder at the Ishapore Mills in Bengal: Published in 1862.
The English service powders cost 5Β£. upwards for the 100 lbs say 50 rupees. The best sporting powders sell in London about 2s to 3s per lb, 10Β£. to 15Β£. the 100 lbs. Blasting powder is sold by dealers at from 50s to 75s per 100 lbs.
The entire book discusses the manufacture of powder, and the facility is in India, but it mentions prices in London, so they should be relevant.