if you cut it/have it cut, and its good (no defects, mineral, or rot) i wouldnt sell it for less than $5bf (board foot). for one that straight, that big, and that long, prolly get $8 bf.
we sold one last year (veneer walnut) that was 24 inches (measured at the small end) 16 ft long. 400 bf total brought 2000 dollars.
just for comparison, my little office scale shows 30 inch diameter x 16 ft length at 676 bf. multiply that by 5 = 3380 dollars.
from what your decsribing, you have a 10,000 tree growing in the bottom of the holler (if its good).