-1 acre is 43,560 sq ft. 1/3 is 14,375 sq ft.
-I haven't bought mine for my 2 acres yet this year, but the Heartland Co-op in Waukee is around $25-30 for a bag that covers 12,500-15,000 sq ft.
-Five applications is overkill. 1 spring, 1 fall, and spray any weeds with Trimec Classic...