I am thinking about buying a $35 Raspberry Pi model B+, it has 512MB of RAM, 4 usb ports and an ethernet port.
http://www.element14.com/community/community/raspberry-pi/raspberry-pi-bplus

There is also a stripped down version with 256MB of RAM. http://www.raspi.today/raspberry-pi-model-a-plus-out-now/
The model A+ has only 1 usb port and no ethernet, so it would additionally need a usb hub and a usb Wi-Fi dongle.
Does the model A have enough memory to run NEM?
http://www.raspberrypi.org/wp-content/uploads/2014/11/A-_Overhead.jpg