Installation for Raspberry

Raspberry Pi 2 Model B (~ $30)
Alternative: Raspberry Pi Model B+ (~ $30, predecessor of the RPI 2 Model B)
Case for the RPI (~ $10, if you want the HDD, buy HHD enclosure too for ~$10)
Aluminum heatsink set (~ $5)
Power supply (~ $9)
MicroSD card (~ $8-$17, I recommend getting one with at least 16GB of space, and class 10)
Hard Drive WD PiDrive 314Gb, (~ $40, if you want to use fast and heavy storage)
Ethernet cable (~ $8)
Alternative: WiFi USB adapter (if you don’t want to use a cable)
Optional GSM getway if you plan to not use Voip (~ $200, for a Goip 4 channels)

Global price should be ~ $200 in standard (without the GSM gateway).

You different environment to install the Voxibot suite for Raspberry :