If you find .060 or .050 diamond plate, or 5 bar tread plate which is what it sounds like you're after. I buy it for about $85 for a 4 X 8 sheet at an aluminum wholesale distributor. It weighs nothing- really light and comes polished. I've used it on many things and its easy to work with and cut at that thickness...
I've also seen what the others are talking about- its rubber and used as a mat for flooring, and pretty durable. I sourced it once but never bought any, and it was through a marine distributor that I found it- was available in many colors- some really ugly.
Tread plate is really common in Europe- you never can find real DP there, its ALL tread- I like the DP better, but just my taste- I've sandblasted it and black anodized it for my Harley- flat black DP- beautiful stuff...
