yar i think one sheet was for about 1500rs. but overall just damping your trunk will cost around 10k....but i maybe wrong because these are a few months old prices.
i have also used foam....installed it myself. shop people indeed do a kachraa kaam. useless...and they charage around 1500rs. haroon radio in khi was offering to foam my trunk for 1500rs. but i bought my own foam and samad bond and did it myself.
its the best u can do in less than 150rs