Pricerange: $

http://www.reprappro.com/new-electronics-new-reprap-new-distributor/

It is based on the same ARM processor as the Arduino Due, and can be programmed using the Arduino IDE (and also Eclipse).  And we have written a new open-source RepRap controller program for it called RepRap Firmware, which can be downloaded from that link.

The Duet has both USB and Ethernet, so you can drive it with a conventional RepRap control program like Pronterface, or use it to control your RepRap from a web browser.