well i want a sample of either biofoam or depron so that i can search for it locally 

Harsh go to sitaram stationers at south ex market part 1,they stock biofoam and i regularly buy from them.

what's the cost ??

Biofoam is available for RS 250 per sheet,its quite big and foamboard for RS 350,you can also get balsa wood from there if you want.

thanks mate for the info 
will check it out !!!!