This chocolate 3d printer should cost only 99 USD and cartridges with sweet brown goodness only 5 USD. It doesn't get better then that folks.It is still under development.
http://www.chocabyte.com/
For another more advanced chocolate 3d printer see:
http://diy3dprinting.blogspot.com/2014/01/chocolate-choc-creator-v1-3d-printer.html
If you want to make your own simple chocolate extruder to attach to your desktop 3d printer go here:
http://diy3dprinting.blogspot.com/2014/02/how-to-print-with-chocolate-on-your-diy.html
http://www.chocabyte.com/
For another more advanced chocolate 3d printer see:
http://diy3dprinting.blogspot.com/2014/01/chocolate-choc-creator-v1-3d-printer.html
If you want to make your own simple chocolate extruder to attach to your desktop 3d printer go here:
http://diy3dprinting.blogspot.com/2014/02/how-to-print-with-chocolate-on-your-diy.html