As part of their Pi Day celebration, StackSocial offers The Complete Raspberry Pi 3 Training Bundle for $19. That's a savings of $195 and the lowest price we could find. This course bundle includes Wireless Penetration Testing with Kali Linux & Raspberry Pi, Cluster Pi: Build a Raspberry Pi Beowulf Cluster, Raspberry Pi Essentials & Extras, PiBot: Build Your Own Raspberry Pi Powered Robot, Raspberry Pi: Full Stack, and From 0 to 1: Raspberry Pi and the Internet of Things. Deal ends April 12.