Currently, it costs about 50$ in parts, and all the parts are available on eBay. No BGA or other difficultly solderable ICs are used (with the obvious exception of Pi Zero). User interface is written using Python, and there’s a phone-tailored UI framework in the works (so far, it uses pyLCI for interfacing). However, even current state of it is further that other projects have come.
Each Friday is PiDay here at Adafruit! Be sure to check out our posts, tutorials and new Raspberry Pi related products. Adafruit has the largest and best selection of Raspberry Pi accessories and all the code & tutorials to get you up and running in no time!