Are fed auditors going to come around and demand 27% of my garage sale and e-bay receipts?
You need to do some research. Only new items sold at retail are taxed. Your garage sale items you sell aren't taxable. It's clear that you have an agenda other than trying to educate yourself to the greater benefits of an NRST over a flat tax and way more than the income tax.
Freedom calls for being able to choose to say no to a tax -- the retail tax, don't buy retail -- because you choose an alternative wherein you aren't required to pay the tax; compared to not being forced with threats of jail and financial ruin if you fail to pay the income tax. Even if you pay the income tax the IRS has a history of abusing people that have paid their income tax.
What if I make and sell quilts or pottery or other craft items? They are new. What about the services I sell? Will I be taxed when I mow Mrs. Spinster's yard for $10 or fix her chimney for $100?