Variable costs change in proportion to production volume, such as packaging, raw materials, and delivery. Fixed costs (rent, insurance, loan repayments) remain constant regardless of output. Recognising the difference is crucial when negotiating supplier pricing, as variable costs are often more open to tradeable adjustments (e.g., bulk discounts). Buyers who understand cost structures can challenge inflated fixed allocations or negotiate on genuine variable elements. This knowledge is vital in price breakdown discussions and in cost-modelling negotiations.