Over on YouTube, Elektor have uploaded an overview of their Elektor SDR Hands-on kit. The €49.46 kit is an Arduino shield, that turns an Arduino microcontroller board into a 150 kHz to 30 MHz capable SDR receiver. It is based on the G8JCFSDR, which is an RF front end downconverter that allows a PC soundcard to be used as an SDR analog to digital converter.
To compliment the SDR is a book that goes over introductory topics such as shortwave reception, explains signal to noise ratio and interference, different types of antennas, software, digital modes, SDR measurements, receiving and finally WSPR and QRP transmissions. Overall this looks like a good kit for learning about the technical basics of SDRs.