The last-ever penny will be minted today in Philadelphia

Setting prices to avoid the need for pennies is probably technically challenging given the combination of requirements to post prices and sales taxes that don't always round the same way.

If the effective tax rate is 7.432%, you can price single items so that the price plus tax ends up in a multiple of $0.05, but if you get a purchase with multiple items, you either need to round somewhere or post prices that are like $9.346263437.

sales tax should be charged per item, not for the total transaction, so that it's possible to list prices that include the sales tax.

Good point. I forgot about sales tax. That also seems fixable by adjusting tax law, but adjusting law is always more hassle.

For example, $0.93 * 1.07432 = is $0.9991176 exactly, which rounds to $1.00. But if you buy a dozen such items then $0.93 * 12 * 1.07432 = $11.9894112 exactly, which rounds to $11.99.

Sales tax varies by state/county/city. It is generally not cost-effective to have each individual store label all their products with local sales taxes applied.

It generally is, or at least per category of items. Different items can have different (or none) sales tax rates.

I see this excuse all the time, but why not? This calculation does not need to happen more often than the product prices are adjusted. There's no difference in effort between labeling something "$5.52+tax" and labeling it "$6".

The difference is where the product is labeled. Is it labeled nationally like Arizona Iced Tea? Is it labeled at a regional bottling facility? Or is it labeled at the store itself? And what about when tax rates change, you gonna go pull all the labels off everything in the whole store and update them?

Most of this could be resolved by not putting the prices on the products themselves, but that isn't as good of an experience for the shopper.

Imagine a world where they just posted the price you would pay at the register on the shelf instead of some number that is ~93.082% of the price you would pay.

I know it's hard to imagine the price on the shelf being the price that you pay, but I believe it is possible even in complex tax situations.

I live where there is no sales tax, so it's not hard to imagine!

But good luck convincing every state, county, municipality, and other weird governing body that requires something other than that and also collects a weird sales tax.

Or go with the solution that papers over all that nonsense: a flexible and maximum $0.04 per purchase discount.

I mean it's not on the state, county, municipality, or weird governing body to put the prices on the shelf at the store. Nation wide advertising might be different (is that still a thing? There were always asterisks that made a dollar menu not always a dollar anyway), but the literal price on the shelf / menu / ... at any given physical building could price things appropriately for the physical location that they are on.

I live in a place with a fixed VAT (that is included in the price on the shelf / menu / ...), but grew up in the US in several different weirdly taxed localities. It's just such a silly argument to say "we can't write the correct price on the shelf because the laws vary." The register knows the correct price, the labels on the shelf are computer generated, and updated regularly. The labels at many nation wide fast food type places are displays anyway.

If Baarle-Hertog and Baarle-Nassau can make it work I feel like it's at least imaginable that stores that already automate this weird complex tax code could print accurate labels instead of inaccurate labels, with an accurate calculation at sales time.