[thesteamboat]

It doesn't necessarily need to. We could have a `digit-sales tax', i.e. count the number of digits in the item cost and add a tax at that percent. Something less than $10 only has a 1% tax, while something costing $10,000 has a 5% tax.

Clearly the numbers should be adjusted if someone wants to turn this into a serious tax proposal, but it seems possible to design a progressive sales tax.

[jsankey]

It's not quite so simple. Many non-essential things are cheap (e.g. iOS games), and many essential things are expensive (e.g. housing, transport). The line between essential and luxury is also subjective. So you have to start categorising, and things get messy.

[paulddraper]

Costco would be a bad place to shop.