a. why would it slow down retail and other businesses
and
b. cause a black market? don't we already have one?
Because it punishes people for spending money.
Which reminds me: If we do end up with a national sales tax, will they also tax the sale of stocks and bonds?
I would hope so.
Surely if a poor woman must pay tax to buy her children shoes so they can walk to school . . .
then a rich person should pay tax on the purchase of stocks and bonds to accumulate wealth.