If Camille is being charged more based on the volume of the box and not the weight, then the best choice to save on shipping costs would be to choose a shipping option that minimizes the volume of the box while still fitting all of her items. This is because a smaller box will have a smaller volume, and therefore cost less to ship.
For example, if Camille is shipping a few small items, she could choose a flat-rate box that is just large enough to fit her items. This would minimize the volume of the box, while still ensuring that her items are protected during shipping. Alternatively, if Camille is shipping larger items, she could choose a shipping option that allows her to disassemble the items and pack them in smaller boxes. This would also minimize the volume of the boxes and reduce her shipping costs.
Overall, the key to saving on shipping costs when the volume is the primary factor is to choose a shipping option that allows Camille to pack her items in the smallest possible boxes, while still ensuring that her items are protected during shipping.