[kerkeslager]

I'd actually go further and say that taxes should always be included in prices, even before checkout.

A common anti-poor talking point is that poor people don't make and stick to budgets, but corporate refusal to include tax in prices means that you can't reasonably tell how a given purchase will affect your budget beforehand. A simple trip to the grocery store means that you have to know what taxes apply to every item in your cart before you go to checkout to be able to know how much you're spending. That's not reasonable for the average consumer. If you really think it is, go ahead and try calculating your total of 20+ different grocery store items before you check out--you'll fail.