&gt; [0] this is true beyond just institutions, too; &quot;economy&quot; packs of products frequently sell for higher per-unit costs than packs with fewer units per pack, because enough people assume that the cost is lower and don&#x27;t do the math.<p>Assuming the &quot;economy&quot; pack is the only offer you visit a distinct store for and the good is perishable (so that stockpiling doesn&#x27;t work), then it might be cheaper if you factor in the time you need to reach said store, shop there and get back home into the &quot;cost&quot;. The less often you have to go shopping, the more time you save.<p>That is especially true with cat foods when your cat is a picky eater and only eats certain food from a certain place which is most unfortunately at the other end of the city...