Theoretically, buying combination packs or buying an item in bulk should save you money. You’re giving the retailer more money, right? Only the pricing logic of big-box stores doesn’t really see things that way, and that’s where Target Math comes from. Target Math is when you pay more per unit for buying in bulk, like this combo-pack of printer ink where you pay an extra eight cents for the privilege of having your cartridges in one box. [More]