My local flier also has the 40 lbs for $9.99. I still have three bags in the basement but we've burned over two bags so far this season.
HD and / or Lowes usually has this sale on Memorial day and Labor day weekends. Last year I found out that it is very localized. The Lowes about 40 miles away had it one weekend while my local stores had it a week later.
Since lowes is right around the corner from the hotel here in Columbia have picked up 8 twin 20's. Did notice that the sale sign does not mention limit 2 this time.....