Drobs, the last I heard, a couple different guys were making/selling hand tools for punching out the hulls - MannyCA on the Castboolits forum, and Kevin (aka Capmaker) on the Gunslingersgulch forum.
As Maillemaker hinted, buying the potassium chlorate, antimony sulfide, sulfur, etc, from a chemicals retailer is more economical than buying that primer kit.
Be advised, though, making caps is rather tedious and time-consuming. It's nice to have that capability, but if commercial caps are selling for $10 per 100, and it takes you one hour to make 100 DIY caps, you are essentially working for minimum wage.