Larger bags of kibble
The current system has single serving bags of kibble - what in real life would be sample bags.It would be an improvement if you could buy bags of varying sizes. There could be three sizes of bags of kibble - 5 servings, 20 servings and 80 servings.
They would cost appropriately more, but as buying in bulk saves a person money, the 20 serving size would cost approximately the same as 15 servings, etc.
When you go to buy dog food in real life, the tiny bags are free, but lead to purchases of larger bags of the selected kibble. This would bring more accuracy to the kibble purchase aspect of this game.