Hi, Thanks for your response! Yes, I absolutely agree about income tax - that you need to pay in the country where you live or have a citizenship (well, USA has more strict rules, but I am not a US citizen).

My concerns are more about sales taxes (VAT, GST and whatever other names they have). I am form EU, and in EU we need to pay sales tax (VAT) when we sell services to any EU country. And when someone sells physical goods to EU (not sure about services though) the seller needs to be registered for VAT in EU, no matter where the sale comes from. When I learned about this EU rule, I thought that there may be similar rules in other countries. I've done some research and it turns out that there are actually sales taxes in almost all the countries, but you need to pay those only when you reach a sales limit, which is usually quite high.

As I understand, in practice, no one registers for sales taxes in other countries. And there are no services that can do this for you which is a sign that you don't actually need to do this. But still I am not sure about all this. The rules are usually very clear about e-services (like selling music, or ebooks, or downloadable courses) and physical goods. But when it comes to distance teaching, it's not so clear. By the way, for e-services when you really need to register for sales tax in every country you sell, there quite a few services that do it for you.