I’m still a student and never used post services in my life, so don’t be surprised if I say something dumb.
So, I am from Serbia and I know how I can legally buy stuff from America by using several shipping companies that give you a US mailing address (which is their warehouse, which you use to buy items unless you can get them shipped directly here) and then those shipping companies ship it to you from their warehouses for relatively cheap, taxes included,etc, if an item is around 100 or 200 dollars, the whole process costs an additional 20-50 dollars.
However, what if I wanted the opposite and to sell items I own to Americans or other westerners? For example I can get a bunch of older, but still working computer parts here for dirt cheap, since our salaries are 10x smaller than American ones, so prices are also much smaller, but I see that in America the same items (old cpu’s, gpu’s,etc.) sell for several times higher, for example a old working GPU I recently sold to someone for 9 dollars costs like 40 dollars in America (used), so how does the whole process work and do I have to pay anything for the shipping and taxes or can the buyer be the one that pays?