Ok, I will see what all I can answer for you.
#1 - Yes, you can buy styrene in sheets. It comes in all sorts of thicknesses and you can also get just about any shape. Most shops have a rack of Evergreen or Plastruct of it.
#2 - Resin is stuff that you make a mold and pour in as a liquid and it dries hard. I belive the most recent copy of FSM has a basic how to on resin casting.
#3 - Alcad is some paint that you can use to simulate metal finishes with. You apply it on to a black base and when done looks very much like metal. I have not tried it myself , but I have seen the results and they look pretty impressive.