Nonsense my old conservative arse. A national sales tax invites the federal government into all manner of intrastate commerce. You have authorized them to knock on your door and audit your books if you sell your neighbor some cordwood or if your child opens up a lemonade stand. How exactly does a national sales tax limit government?
READ about the Fair Tax, what and who it taxes, speak with knowledge and you might gain some support.
Don’t knows how it works where you are, but most places sales taxes are for sales by retail businsses only, not stuff sold privately. The only people who might be audited are retail businesses.