Unless you are calculating the response of your room, you need not get 'acoustic' foam. The same material can be gotten from packaging manufacturers, and there is one in Jurong/Ayer Rajah. Refrigeration company, .. I had them make pyramid profiles in 8 X 4 ' sheets 75mm thk, had 10 sheets made for about 350 SGD. Look up your industrial guide.
If you are calculating your room response, then you might want to get acoustic foam. Foam does not really alter room EQ as much as it kills reflections, - acoustic traps do more, and there are acoustic traps made of FOAM. But if you are looking to line your walls, packaging foam ( the kind you get in computer boxes) are all you need. They will kill refelctions.