Show exactly what the delivery price includes
For gas, distinguish a refill from a cylinder purchase and state which sizes, brands, regulators, or accessories are available. For water, list the volume and whether the price includes the container, a deposit, or an exchange. Clear details prevent customers from comparing different offers as if they were the same.
Keep the stock and listed prices current. If availability changes during the day, confirm before dispatch and tell the customer how you handle a substitution or unavailable item.