>>11198564maybe you don't know this, but especially with particular couriers like FedEx, maxing the number of items send on a single shippment is worse in almost all cases.
Pic related are some calculations I did for my specific case (Mexico, almost all gunpla) and found that the best price per item is when the shipment is at 13k jpy. At that price the Lah Gundam in the shipment costs only 1,085 jpy to ship. Add another item (standar HG box) to the package and the shipping cost balloons by a whooping 3,000 and the price to ship the Lah Gundam increases to 1,234 jpy. That is what the other anon is referring to with clever combination.