The US is the exception.

In most countries, the buyer has to pay the standard sales tax, which is levied on every product regardless of where the seller is located. Tariffs are usually not relevant because they only apply to shipments of very high value.

In the US, the buyer has to pay the sales tax, but apparently only in some states and sometimes not if the seller is located in another state - and not if the seller is located in another country?? Now, however, tariffs have to be paid on all imported products, regardless of their value. This is an unusual situation.