I provide kits for some of the electronics projects that I build because I purchase the PCBs and components in quantities to save money, so I have spare parts. Since these kits can be interesting to other people, I'm making them available for purchase. Taking handling into account, I make very little money selling these kits. If you're interested in the kit, it's probably cheaper for you to get the kit from me rather than making your own PCBs and getting the components from the store (specially if you want the "PCB only" kit).
If you want to purchase some kits, email me to get a quote including shipping (please include your location and any preferences regarding shipping).
I understand that some people may be unable to solder the SMD parts included in the kits. I can also offer built and tested kits. If you're interested in this, contact me.