On the topic of displaying something like "Sales Tax: $0.00" because your store does not collect sales tax in a particular customer's state is a VERY bad idea. I will copy-and-paste from our documentation available within TaxCloud in our the "Sales Tax Policy" area:
Retailers are only required to collect sales tax on transactions into states where they are physically located (with offices, retail showrooms, warehouses, or processing facilities). Although retailers are not required to collect sales tax from out-of-state customers, these customers still technically owe any applicable sales tax to their state, and are supposed to self-report and remit these taxes voluntarily. Unfortunately, although not surprisingly, less than 0.04% of consumers actually comply with this requirement (which has been law in most states for over 50 years).
Recently, states have gotten very aggressive about pursuing retailers who mistakenly print "Tax: $0.00" on a customer's order/checkout page. This creates liability for the retailer to owe the sales tax due because the consumer can rely upon the retailer's representation that no tax is due, even though it was in fact a taxable transaction.
TaxCloud offers the following guidance to retailers:
If you must have a line on the checkout page that references "Tax" or "Sales Tax" it should actually say "Tax to be collected" or "Sales tax to be collected"
Include a very clear sales tax policy statement which is not unlike a Privacy Policy Statement or Shipping/Returns Policy Statement. This is important because several states have recently passed laws prescribing exact language which must be presented to customers in those states when a retailer doesn't collect the sales tax due at the time of checkout.
IMPORTANT: FAILING TO IMPLEMENT THESE RECOMMENDATIONS COULD RESULT IN POTENTIALLY SIGNIFICANT LIABILITY ON BEHALF OF THE RETAILER FOR UNCOLLECTED SALES TAX IN A PARTICULAR STATE.
IMPORTANT: TAXCLOUD IS NOT PROVIDING TAX ADVICE. RETAILERS SHOULD CONSULT WITH THEIR ACCOUNTANT(S) AND TAX COUNSEL FOR CERTAINTY REGARDING VARIOUS STATES NOTICE PROVISIONS AND REQUIREMENTS