We are more expensive than the US for most musical stuff I guess (unless you are buying a Wal) but absolutely not more than mainland Europe. 10 years ago I could rely on Thomann to be the cheaper source for most things but that's long gone.
There is import duty on all goods coming into the EU, and that applies to businesses/importers. No such thing as free tradeSales tax (in our case VAT) is an additional tax that is applied at the point of retail.
Dude I worked at a guitar store on denmark street for three years off and on in ordering and we never paid a single import duty on a guitar or Bass from a US manufacturer. Ok, we are now going back to 2009-2012, but that doesn’t seem that out of date.