Usually, items below 800 USD in customs value are not subjected to further taxation

Unfortunately this is no longer the case in the US, the de minimis exemption was suspended last year:

As of August 29, 2025, everything changed. The U.S. government eliminated the de minimis threshold for all countries, making the rule apply regardless of country of origin. That means every shipment — regardless of value or origin — will now go through formal or informal customs entry and be assessed import duties, taxes, and fees.