How was this costume created and where can I go to do something similar myself?

Here’s the link to the costume to which I was referring: http://colin-midwest.deviantart.com/gallery/#/d4qupw7

I’ve always been fascinated by this kind of sculpting, but I have no idea how to get into it myself. The artist said that is was created with expanding foam and fiberglass. Can anybody link me to a website with more details on how to start some sort of (smaller) project like this? Also, if you’ve done this sort of work before, can I get an approximate cost on the materials necessary?