I buy this flour----it's such a great deal! I use a 2 cup measuring cup to scoop it into a large Tupperware container---I use the flour from here when making bread every other day.
The rest I just leave stored in he big bag, folding down the top securely. Then it sits on a shelf on an open island in the kitchen, or in the dining room where I have overflow Costco purchases! But honestly, it keeps just fine in the big bag. It takes me about 4-5 months to use up the whole thing.
ETA: the size I buy is the 50# bag, my only Costco option.