Where can I buy styrofoam in it raw form to mold into styrofoam objects?

I want to make shaped pieces to protect a wooden type box that I ship all over ? I've had no luck with the peanuts or anything else so now I wan to make a molded form that will fit into the corner of the shipping box so that the wooden box will not move during the shipping process. CONTACT me @ daugrty@att.net. MY NAME IS KENNETH C. Sept. 20-2010