Online shopping will soon be more expensive following a decision Thursday from the U.S. Supreme Court that says states can require internet retailers to collect sales tax.

The decision overrules a 1992 Supreme Court precedent that said online companies only had to collect sales tax if they had a physical presence in that state. That's why online shoppers sometimes see sales tax added when they check out.

But brick-and-mortar businesses have complained they're at an unfair disadvantage by having to charge sales taxes while many of their online competitors do not. The former commissioner for the state Department of Revenue Services estimates that number for Connecticut is about $100 million. State Sen. Bob Duff calls it "a game-changer from a revenue standpoint."

"States have been losing billions and billions of dollars over the years because of the fact people have been switching to online shopping," Duff says.

The Connecticut Retail Merchants Association released a statement saying in part, "Today's U.S. Supreme Court decision is good news for retailers and consumers: a long-overdue leveling of the playing field across the retail industry."

Some internet companies had opposed collecting sales tax, saying local tax laws vary widely across the country and would be a logistical headache for small retailers.