I've only been refused once by a US reseller. Everywhere else in the world has agreed to put $39 on the labels. I got a very large box from RPM which I could comfortably fit in with no tax.
But remember since January 2021 Ebay, Amazon, AliExpress automatically add the vat to the amount you pay on pretty much everything over Approx ?40. It just annoys me when the tax is more than the item.
I find that going direct to the seller and asking for a discount instead of ebay, you can get better deals as they don't have to price in Ebay's take and if you don't ask you won't get.
Also check Amazon's country sites. US, Germany etc as stuff can be way cheaper and then Amazon ships internationally internally. It was on Martin Lewis's show. Even Bosch dishwashers from Germany etc. When I moved in 2020 it worked for me. I bought loads.
Now before I get hate mail, I do try to buy everything in the UK but with a recent hideous one way divorce, funds are low so it pays for me to shop around as I'm keeping this bike as it's the last one I'm buying and I want to get it perfect.
Before the divorce I was literally paying more corporation tax through my business than Apple, Amazon, Starbucks etc combined. Honestly. They pay less than ?2000 in corporation tax in some cases....
Also, always pay by credit card as you are protected but in decades of buying from abroad I've never had anything but great service from abroad. I can't say the same for UK sellers apart from Sportsbikeshop. They're the best.
Jamie