"More than 40 states had asked the high court to overrule two, decades-old Supreme Court decisions that they said cost them billions of dollars in lost revenue annually."
...
"The cases the court overturned said that if a business was shipping a customer’s purchase to a state where the business didn’t have a physical presence such as a warehouse or office, the business didn’t have to collect the state’s sales tax. Customers were generally responsible for paying the sales tax to the state themselves if they weren’t charged it, but most didn’t realize they owed it and few paid."
https://apnews.com/332abb7455cb4b60b2effc0852ff3c89/High-Court:-Online-shoppers-can-be-forced-to-pay-sales-tax
Sales Tax on the Internet
"Despite what you sometimes hear, however, some Internet sales are subject to sales tax, and even when a site doesn't collect sales tax, consumers are technically responsible for remitting any unpaid sales tax on online purchases directly to their state.
...
Under the RTPA, however, any seller who sells through an electronic marketplace like Amazon would not qualify for the small seller exception."
Consumers May Be Required to Report and Pay Sales or Use Taxes
"For consumers that order tax-free items online, but live in states that charge a sales tax, they are technically required to report that purchase to their state tax agency and pay the sales tax directly to the agency. When consumers are required to do so, it is often called a "use" tax."
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South Dakota wanted out-of-state retailers to begin collecting the tax and sued several of them: Overstock.com, electronics retailer Newegg and home goods company Wayfair. The state conceded in court, however, that it could only win by persuading the Supreme Court to do away with its physical presence rule. After the decision was announced, shares in Wayfair and Overstock both fell, with Wayfair down more than 3 percent and Overstock down more than 2 percent.
The Trump administration had urged the justices to side with South Dakota.
The case is South Dakota v. Wayfair, 17-494."
https://apnews.com/332abb7455cb4b60b2effc0852ff3c89/High-Court:-Online-shoppers-can-be-forced-to-pay-sales-tax
This is really a state issue. If your state decides to charge you sales tax for a purchase made online...or in a brick n mortar location...your fight will be at the state level.