At first we were just going to put a cheap piece of carpet in the back to cut down on the noise. After a few trips to Lowes I had the entire thing carpeted and trimed. It was not as hard as I thought.
The kicker, it costs less than $60! It is Berber carpet, low pile. My wife picked out the color. She is great with color. At first I was stuck on the fact it was indoor house carpet and not automotive. Now I like it fine. the automotive carpet was going to cost around $200. I used regular foam padding in the bed and Chevy Duty's floormat padding in the front. It's the same stuff they charge $15 for pre-cut but it's only $8. Used 3M spray adhesive to glue it all down.