If you're asking about the kettle build, you can build it using mostly hardware store parts. I ordered the o-rings and washers from the recommended seller. I also used a hole saw instead of the expensive hole punch the electric brewery recommends. For a hole saw, use lots of cutting oil and go slowly, then dress the rough edges GENTLY with a round file.
For the control system, I use an SCR (silicon-controlled rectifier) from e-bay or Amazon (http://www.amazon.com/RioRand-Controlled-Controller-Electronic-Thermostat/dp/B00MFEA5AE?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o07_s00) to control boil intensity. Edit: You'll need a fan to keep the SCR cool. If it gets too hot it'll turn off.
I use an STC-1000 and a relay (http://www.amazon.com/Packard-C230B-Pole-Contactor-Volt/dp/B001KGSJ74?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o04_s00) to bring water to a specific temp without having to watch it constantly.