What is the insulation value of....?

hey i want to build a sort of shed/summer house i live in london but i don't know what kind of insulation to use I've sort of decided on Fiberglas insulation Styrofoam insulation celotex or king span (same thing different brand) or rockwool that B&Q were selling for �3 which i am kicking myself for not buying back then but anyhow could somebody tell me what the insulation value is per � i cant find it for any of these anywhere