The government needs to provide a service if we ever want taxes to be included. Taxes vary by city and can even depend on where you live, so sellers wouldn't be able to give you a price until you say where you are and where you're from for some sales.

That's why you basically need a third party if you run an ecommerce website, unless you have a team to track down every time a county or city changes their taxes.

You could exclude prices on preprinted tags and just regulate shelve pricing and store signs I guess.

>That's why you basically need a third party if you run an ecommerce website, unless you have a team to track down every time a county or city changes their taxes.

Every ecommerce site already has to calculate taxes on checkout, already has a third party for this information (usually the payment processor).