If you really need to do this in the absolutely least expensive way and are not convinced or concerned by the demonstrated inferiority of asphalt based sound deadeners, go to Lowes and get a roll or two of Peel & Seal. This is the least expensive option and you won't have to worry about shipping costs. I can see no difference in Peel & Seal and the asphalt based aluminum skinned products in this review. If you are going to live dangerously, do it right.