While you're still trying to figure that one out... also figure out how much someone needs to earn, before taxes, to pay for that $100 "untaxed" item (plus taxes).
Keep adding it up, and you'll see that that $100 item already costs $130 today.
Which set of assumptions do you want me to figure it on. Wages stay the same, after tax prices go up. Wages are reduced, after tax prices stay about the same. Or some fairytax reality where everyone pockets more money and miraculously prices stay the same. It is a waste of time to compute anything if you are going to have fairytale assumptions.