ISBN foreign or US?

Does any one know how a non-US ISBN would impact the business end of things, such as with Smashwords or PoD services with sales mostly in the US?

I am a US citizen but a permanent resident in the Czech Republic, so it appears from what I read that I have the option to get ISBNs in the US or in the CR. At least I haven't run into anything that says otherwise. ISBNs are horrendously expensive in the US, so I am tempted to try to do it where it is actually a normal form of registration in the Czech Republic. However, my tax issues will be handled in the US only. Given that the IRS would double tax me anyway, there is no reason to involve another country in that.

But I wonder if that will be complicated if I have foreign ISBNs and my tax identity is in the US. Does anyone know? Do publishers with foreign ISBNs have to pay international tariffs? Thanks for any hints.

Thanks for the ideas, Shelleyo. I will look into that.

I know about Canada but they have a special agreement with the US on this sort of thing, so I am not sure that the same rules will apply.

I have legal residency in both countries, spend part of the year in each, will soon be a citizen of both, get taxed by both, write in both, publish over the internet. "Where are you based?" is becoming a problematic topic for a lot of people these days.

The main issue is that bit about the retailers. If retailers treat them the same and I'm not going to suddenly run up against someone saying, "Oh, that 70 percent royalty category is only for US ISBNs. You get 30 percent. So there."

Thanks, Captcha. That is very helpful.

I'm not an international tax expert either but from what I have seen in practice, where you are taxed has much more to do with the laws of the countries you associate with than with any overall standards. The US taxes all citizens on self-employed income of any kind no matter where they live and no matter if that income has already been taxed by a foreign country. The minimum limit is $400 per year. So, if you are a US citizen and are self employed of any sort and make more than $400 a year anywhere, the IRS wants your money, period.

The Czech state is much more reasonable about this. They want to know about all your income but they only tax income made on their soil. It doesn't really matter if you're a citizen or not. If you make money in the CR legally they are going to want to tax it. But you can be resident in CR and make money abroad that is taxed abroad and not be taxed for that in CR. At least this is how I understand it and its the only way I could make any income at all without being taxed twice.

Some people I have talked to say that if I get Czech ISBNs then I become a "Czech publisher" and any money I make as a "publisher" should be taxed here but I can still be a US author and any money I make as an "author" should be taxed there. Apparently, if Author Me doesn't give Publisher Me a cut to publish the books, then I can just "happily" pay taxes in the US.