In EU you have to advertise the price with the tax already included. So even if somebody else is handling the tax rates for you, you have to advertise the correct price on your website depending on where the buyer is.
Yeah, but I assume Amazon lets you either keep the price the same and Amazon then sends you a bill or you let Amazon increase the price and take the VAT directly from the sale.
well. you can also do it the other way around and charge the same price but the VAT component changes.
-e.g. 5€ gross price will result in different net prices depending on the buyers location. hence slight differences in the margin for you
That's easy to work around, just set the total price to the maximum for all possible rates. It does mean that you're pocketing more revenue from countries with lower sales tax rates, but makes it simpler to manage in the front end.
The calculation to make is will you lose in terms of total profit by charging people in Luxembourg 24% more than you would otherwise (3% sales tax vs 27% VAT in Hungary)?
But you probably don't have to show that level of detail until the payment stage, by which time hopefully you do have enough information to determine it.
In contrast, consumer protection laws in various EU states require that the price shown is the full tax-inclusive price throughout, even if it's in big numbers right there on your home page.