What about fees only certain customers have to pay?
An example of this in the US is that companies don't know if you're going to pay their sales tax until they know what state you're in. Would they have to collect all required information before they display any products, (potentially being perceived as http://darkpatterns.org/forced-information-disclosure/) or display multiple prices?
In Sweden, the only real difference is between companies and persons, and the former don't pay VAT, but the latter group should. EU didn't complicate matters, you still pay VAT based on the country you buy from, not where you are located.
So if you make a print catalog and send it to companies, you can print prices without VAT. If you make the same and send to people, you have to include VAT. Same if you have a store, you have to include VAT in all prices.
Webshops usually have a simple global toggle somewhere on the site where you can choose to display prices with or without VAT.
In the US case, you could simply use GeoIP to guess the default and display all prices according to that state, and somewhere on the site have a "We think you are in <state>. Change?" and a dropdown.
It's really not rocket science, and the end result is very nice for consumers since the total you see is always the actual total, not a bullshit number that gets magically larger at the last step.
