The RepRap challenge has a number of obstacles for the interim award.  There are two in particular that seem insurmountable.

1. Maintain a total materials and parts cost under $200 and that 90% of the volume of the printer parts be printed.
2. The ability to print autonomously without a PC attached.

I have to imagine something large enough to accomplish all of the other goals would cost well over $200.00.  If an entire Darwin or Mendel were trasmorgrified King Midas1 style into pure plastic, I would think the plastic alone would eat up 90% of the budget.  Even the best deals around the internet for RepRap parts just the electronics are roughly $215.

I say it seems insurmountable – but if someone had told me two years ago I could one day buy a full kit for building a robot that would make me any plastic thing I could imagine for $1,000.00  I would have laughed at them.

1. or Calvin and Hobbes [↩]