I'm blessed to have a vender come to our local target shoots who sells real black powder and caps at reasonable prices, and who keeps a wide assortment of flints, jags, nipples, wads, patching material including Teflon coated target patching, gun parts, locks, barrels, knife blades, round balls, bullet molds etc.
I'm not sure what we'll do if he decides to hang it up and retire.
There is a local gun store that sells real black but at really marked up prices, I can get Swiss black powder from our traveling vender for what the local gun store wants for Goex.