I just make it as I need it anymore. Keep 5 pounds, maybe 500 caps, and a dozen flints ready on hand and the rest is in separate chemicals, or chunks of rocks. 1. it's cheaper than buying, 2. it's safer than having 100+ pounds of powder lying around for the year, 3. No issue with people out looking for trouble (police and nosey neighbors), 4. The components all have other legitimate uses.
Knapping isn't hard, you literally just break bits off until you get to something useable, most people go overboard and try to make it perfect, and ruin the piece. You can also cheat and cut "gun-stones" (doesn't have to be "flint" exclusively, there are other stones that work as well) with a diamond wheel on a Dremel with some water (the knapped are better, but some stones don't knap very well, and need a little more meat to them to hold up).