After the 1933 Emergency Powers , America no longer had gold and silver coin as it’s monetary system, and was utilizing the Federal Reserve (which is neither) system of trading debt notes as the “legal tender” of exchange.
Constitutionally, a person could not lawfully pay for anything, as the Constitution was never changed in this regard. Additionally, the Constitution had no mention of debt exchange, prohibitive or otherwise. So in order for the Government to maintain “honor”, it devised a NEW set of laws to govern the alternative monetary system which would reside along side the Constitutional monetary system. Both systems would exist, but only one would be “acceptable” to use in commerce. That would be the system of debt exchange, and it is governed by the Uniform Commercial Code.
The UCC or Uniform Commercial Code is an extensive multi-volume plethora of regulations, which governs every aspect of the monetary system in America, which is based on debt. The code like other codified laws is at best obfuscated to the average person, and to truly understand what it allows, prohibits, or implements takes an immense amount of study, and practice.
Items familiar to you that are regulated by the UCC are:
Birth and Death Certificates
Why Birth Certificates?
This will be covered in pt4.