I wanted to buy some carpet to replace a worn trunk carpet for my RR corniche. It's nice stuff...wool, thick, woven, etc. $125 bucks a square foot. What? $1,800 for a trunk carpet? My upholstery guy found some nice wool stuff for $25/ft and boardered it with leather binding, looked just like the original for about $400 bucks all done.
Some years ago I replaced the carpet in my ski boat with the black automotive stuff you get from Home Depot. Looked great. $200 bucks, done!
My bit of advice would be it's impossible to buy it over the internet. You gotta feel it with your own hands and see it with your own eyes to be able to gauge if it's what you want to be staring at in your own car for the next XX number of years.