How can they sell smokes on the Internet?

There’s a site I’ve bought from (for friends, I don’t smoke) that’s located on an Indian reservation near Buffalo NY. When they arrive the cigarettes all say “For Export Only” on the packs and they do not have a NY State Excise tax seal. They are also cheap. Name brands are only $20 a carton (they’re over $40 in stores here in NY).

Ok, so maybe the reservation can be considered a ’sovereign’ nation, and sale to them considered ’exporting’. But how can they possibly resell them to customers in the US without collecting the taxes on them? Is there some loophole or is this just blatently illegal?

Apparently not illegal. Hoever I found on this site:

I also note that Arizona requires sales tax to anything sold by native Americans on reservations to non-native Americans. To this foreigner, it seems to be a state-by-state situation.