Doesn't the US government track all packages and shipping? Wouldn't they notice if a bunch of packages where shipped to or from a particular address without any corresponding traceable money transactions?
What is the best way to ship goods anomalously/untraceable?
There are a lot of reasons one might choose to ship a lot of packages without money being involved. There's also nothing illegal or even suspicious about conducting barter through the mail.
Umm...haven't you heard of the
United States Postal Inspection Service, whose purpose includes "protect the nation's mail system from criminal misuse". And haven't year heard that not reporting taxes on goods or services is a crime?