Hi,I buy 50lbs of flour at a wholesale bakery supply store along with oatmeal and sugar and other baking supplies. To store opened or surplus flour and oats I do put them in the freezer orginal bags in a trash bag. So they do not stick to the shelf and rip open. For storage containers I went to Dunkin Donuts and asked if they had and extra large containers like the 5 gal buckets for their frosting or filling.
They sell them at a dollar a bucket. You could ask at your super market or a bakery too. Good luck Sheri Maine