Padding. 1  Cost: Ranges from $3.50 - $6.50 per square yard. 2  Pad Type: Rebond, synthetic fiber, rubber, wool, felt. 3  Pad Thickness: 3/8, 7/16, 1/2. 4  Pad Density: 6 to 10-pound density.  Typical Lifespan: 10 to 20 1  years. Carpet Installation  Cost.