American here (who lives in Europe). America has a system of sales tax, where tax is collected by the specific state at the point of sale. Sometimes, the municipality collects sales tax as well.
The US does not have VAT, where tax is added cumulatively along the production or supply chain. As long as the manufacturer is selling to an intermediate (a retailer or distributor), they pay no tax for producing the item (although they will pay a tax on their total corporate revenue, real property the business owns, etc).
The sales tax is not listed on the price of the item. The reasoning is that the sales tax is not being charged by the retailer - they are only collecting it on behalf of the government. So the retailer only presents the price that they collect. Also, with the advent of internet sales, the price can vary based on the buyer’s location because sales tax is based on state and municipality; for internet purchases, the taxes are displayed on the checkout screen. This is the same in retail settings - the clerk will tell you the final price being charged to you.
States with higher sales taxes tend to have lower (or no) state income taxes. States with lower sales tax tend to have higher state income taxes or have higher taxes on other goods (like gasoline) or government services (higher fees). Certain categories of goods are exempt from sales tax - groceries (unprepared foods), some medicines, and in a few states I believe women’s menstrual products.
Taxes and tariffs are applied to manufacturers and distributors only for international import and export.
My opinion: I think not displaying the full price is deceptive. I think not taxing VAT along the supply chain is a regressive behavior that places more of the burden of funding society onto the individual taxpayer while leaving corporations with lower tax bills. The US consumer is bootlicker and repeater of corporate propaganda, so none of this will ever change.