I'd kind of dismissed the idea of a consumption/sales tax as terribly regressive, but it doesn't have to be, and lately I've been wondering what the distribution might look like. To make a sales tax more progressive, you might in effect say that the first $20,000 you spend is tax-free. If you have a 10% tax, then you just give every individual $2,000 cash (and ignore that some people spend less than $20,000 – that's the sort of loophole that can never grow very large).

Given a system like that I'd be curious what the numbers might really look like. How high a tax would we need? What would the actual tax burden look like for different amounts of cash-back? Could we replicate something similar to the progressivity we have now?

But there's still distortions. Consider high Shipping & Handling fees – these are often done because S&H is considered a service, and so sales tax is not levied on that portion of the cost. But a $0.01 book with $7 S&H is clearly bullshit. But who is there to call the seller on that bullshit? Why are goods taxed but not services? I've never been clear on that.