There are so many cost factors involved when it comes to product shipment. For a product's landed cost - it includes the cost of goods sold (cogs), operating expense (opex), shipment cost (packaging, loading, export duty, export tax, custom fees, terminal charges, and freight charges (air/sea).

When it reaches the import port destination, it will also include custom cost - this is often determine if the buyer or seller will bear the cost (incoterms such as FOB, DDP) - but either way, the end product cost will increase.

VAT in Europe averages at 21%. With Brexit, cost of products in UK shoots up with the lack of Europe trade privileges. Commodity imports from China in the US has import Tariff of 11% - 13%. This amount goes to the gov't and the users bear the cost. The underlying reason is to deter import, but at the same time, not enough facility provided for local manufacturing growth.

On top of that there is ancillary cost — which is your payment processing fees (bank charges/cc charges), foreign currency exchange fees.

If its a direct to customer orders (D2C), the price may seem lower, but often times customer still bears the import duty and tax charges. Sometimes, it can cost more than the product itself. Unless if its luxury goods, then this price will be absorbed into the retail price. If users ship parcels, then its often a lump sum price and breakdown is not always visible,

After going through all this, there is also a 5% - 10% chance the product can get lost so there's delivery insurance cost.

There are cost effective ways such as bridging consolidated couriers that tags with the country's postal service - it increases shipment time but reduces cost - but product tracking is not always end to end.

Then there's the whole spicy story on who governs the port. Logistics is an interesting world.