[Turing_Machine]

Indeed. I live in one city and do most of my work in a neighboring city. They both have sales taxes, but the rates are different, and (more important for this discussion) the exceptions (which rate applies to a specific item) are subtly different. I've been here ten years and I still have to think about it -- when I care. Usually I don't bother to worry about it; it's not a significant difference on most individual purchases. A retailer wouldn't have that luxury. And how in the world is a retailer supposed to determine if I'm buying the item in City A and using it in City B, or vice-versa? That happens a lot - the shipping address I give has more to do with where I'm likely to be at delivery time than where the item will actually be used. Will City A start demanding its cut of items delivered in City B? Will I have to pay taxes to both cities? What happens if I rent a mail drop in neighboring Village C that doesn't even have a local sales tax? What happens when a state with major online retailers (say, "Washingham") starts levying a punitive counter-tax on items purchased from a state (say, "Sickinois") that's insistent on collecting mail-order sales tax? That'll do wonders for the Sickinois economy, won't it?