Check this out, if you think that you're paying too much for wood. Even Steve Wall is inly $6.90 bd/ft for 8/4 KD.
http://raleigh.craigslist.org/mat/917325867.html
http://raleigh.craigslist.org/mat/917325867.html
He does say "most" is 4". At the Hardwood Store, the 300+ price is about what you quoted for 8/4 (6.80), but for 12/4 it is 8.40. They don't show 16/4, but I suspect you would see another big jump.
I am trying to give the guy a benefit of a doubt and run my post count up.:mrgreen:
With my luck, I would pay that price, stack it and end up with case hardened walnut!!