I started with a dip kit - Magnalite from Rocketflite. Others are out there too, but I never tried them. Other posters recommended some of them.
I then followed some recipes I found online, then tried modifications (changing the binder for example), and still trying to get it just right. Learning from a local is the best method. IMO.
Like making propellant, I wouldn't do this to 'save money.' I burned quite a few testing. I've thrown out entire batches, etc. Balancing effectiveness, reliability, not having the crumble, not having the 'pop' instead of light, etc are all issues.
Make sure to cover the nichrome wire completely. Any crack after drying that exposes the nichrome will make a failure very likely. The nichrome often burns through here with nothing to light.
The other fun part is making them small enough to fit in the smaller nozzles.