Free: Contests & Raffles.
When using musket caps I have found the ones from Germany (or have German labeling) to be the best. I would have to dig them out to find the exact name of the manufacturer as I have all of my black powder gear packed away for the year. I am sure some others on here know what I am referring to as it has been discussed before.
I recently bought some CCI musket caps, haven't used them yet, but I did notice on the top of the container it says "for reenactment use" hopefully they work