Each country has it's import fees for commercial use. These are often quite large, and, as an import company, you will have to pay them to operate legally.
The reason some of these fees is large is due to governments trying to control the import process, not due to any inherent costs associated with the items, so where these fees apply can not be guessed without having knowledge of the specific laws and treaties involved. As an individual, you've never needed to know these laws and fees
Also, your legal costs to import random things over random borders is going to be quite large. Most importer companies start with one set of items into a single country to defray the legal costs for that one set of items over many items sold. i.e. It's as much legal effort to commerically import 10 cases of wine into the US from France as it is to import 10,000 cases. But importing Cheese from France to the US is a completely different set of laws, and could cost the same as the legal costs for the wine.
The reason some of these fees is large is due to governments trying to control the import process, not due to any inherent costs associated with the items, so where these fees apply can not be guessed without having knowledge of the specific laws and treaties involved. As an individual, you've never needed to know these laws and fees
Also, your legal costs to import random things over random borders is going to be quite large. Most importer companies start with one set of items into a single country to defray the legal costs for that one set of items over many items sold. i.e. It's as much legal effort to commerically import 10 cases of wine into the US from France as it is to import 10,000 cases. But importing Cheese from France to the US is a completely different set of laws, and could cost the same as the legal costs for the wine.