By purchasingĀ cat food bagĀ in bulk, you save money because you have to shop less and can save money on a per-pound basis than with smaller quantities. Such bags are normally packaged with sturdier material to allow the food in them to last longer. Online marketplaces and pet supply stores frequently provide a discount when you are purchasing a bulk amount and it is a more cost-effective option when there is more than one cat in a household.