The Triple K snap caps are often sold as Armsport, not that I have any idea why. The caption on the linked Champion's Choice website is misleading, as what they are selling has neither a brass base nor spring loading. They are just molded plastic.
I have not use Triple K, but have used Pachmayr and Tipton, which are also simple molded plastic. The Pachmayrs are somewhat fragile while the Tiptons last about 20 hits apiece. I buy them by the hundred, which lasts 4-6 months of daily dry-fire practice.
I have also done lots of dry firing with empty cases. This works fine, but the cases are somewhat difficult to insert, depending upon the type of firearm and the size of your fingers. It also tends to fling bits of carbon into the barrel, which may or may not bother you.
There are also many folks who will cut up an old credit card or similar material into a size that fits the breech face, and also add a cutout for the extractor. This supposedly works very well, but I have not tried it myself.
HTH.