Soundproof plugs are the easiest, cheapest and quickest approach to soundproofing your windows, but have significant disadvantages. These plugs are removable hard packed foam plugs that are anywhere from 1.5" to 3" in thickness. The foam is cut to the size of the window opening and is inserted by hand to create a snug fit. This can be done by a homeowner without any expertise and therefore requires no professional installation. Once the foam plug is in the opening it blocks out noise, as well as pretty much all the light that would typically enter through window glass. Foam plugs may be available at the big box stores or through online retailers.