if there is a pepakura file that exists for robo, thats the way to go unless you are an excellent sculptor with money to spare.
if you pep...
Card Stock - 15-30 dollars
Printer - most ppl have one
x-acto knife - 2 dollars
metal ruler - 1 dollar
superglue - 6 to 10 dollars (if you buy from dollar tree)
fiberglass resin - 35 dollars
fiberglass cloth - 10 dollars
brushes - 8 dollars
bondo - 25 dollars
sandpaper - 20 dollars
paint - 10 dollars
now thats not every little thing, but its most of it. you still need harnessing and an undersuit to attach it to.
so round about 150 bucks or more depending on how high of a quality you need.