Always buy your olive oil in full pallets, if possible. When your oil is being shipped with a freight carrier, it is strapped onto a pallet. Whether that is stacked with ten cases or sixty, one drum or four, the pallet still takes up the same amount of space on the truck floor. Therefore, the cost to ship a whole pallet vs. a half/partial is very similar. Save the most money by putting as much on a pallet as possible.
Note: Most suppliers have a one pallet minimum order anyways.