If you want to see expensive try getting a few yards of a rare custom weave done----8 yards of single width fabric can cost you $80-100 per yard in some of them.
Wow, that seems really high. I'm in the process of getting some custom 16-oz tartan woven (Colquhoun weathered, which is not a stock item), and it is nowhere near that much. I'm sure each mill has their own prices, but the range you're quoting seems like quite a premium. Especially for single-width!