Air dried here (where it plentifully grows) is about $3.00~$4.50. Kiln dried goes for around $6.00.
If you're going to go look at the stuff in Clackamas, check it carefully for twists and also for end checks. Improper air drying can cause both these defects. For me, that'd bring the price down to about a buck a foot.
If he sells it as 8/4, the boards he describes would be 34.86 BF, and would cost $348.60 each! For that much money, it'd better be PERFECT!