Quantity   Component name
1 × Raspberry Pi. $39. https://www.sparkfun.com/products/12994
1 × 1 Radio frequency (RF) transceiver for Raspberry Pi. $3. http://www.aliexpress.com/item/High-frequency-rf-wireless-transmitter-module-315-433mhz-tx1-tx5/1713455313.html
1 × Prota OS. http://prota.info/downloads/ if you need a license, drop us a line and we'll arrange one for you.
3 × 3 (or more) RF switches. $29 for 3. http://www.alibaba.com/product-detail/Energy-Saving-Product-Plug-in-Socket_114973224.html?spm=a2700.7724857.35.1.T7P2SB
1 × Bread board.
3 × Jumper wires.
1 × Micro SD to store Prota OS and apps.