As part of a national sales tax, it would not be imposed upon necessities... Such as food or clothing, among other basic necessities. Alternatively, take your "prebate" and give everyone a $5000, or whatever amount of exemption... For example whether you make $25k/yr or $1,000,000/yr you get a prebate/rebate for the first $5000 of federal sales tax you spend. Either option, but not both, is a simple solution to ensure that ensured people are not taxed on the minimum to get by but only on luxuries.

The complaints about this being "regressive" are exactly why the truly fair and equal plan would be better. Everyone pays their fair share, divided evenly among everyone. Very simple.

"but only on luxuries"
The rich should not be taxed on luxury items, it is usually blue collar jobs that build the luxury items and if you put on a luxury tax you will lose jobs!
We want the rich to spend, I say tax the rich at 35% unless they spend(not invest) 50% of their income buying American made stuff, then they would only get the 15% tax rate.