In one of its last opinions for the term the Supreme Court of the US, SCOTUS, today issued its opinion regarding the ability of states to collect sales tax from internet sellers who do not have a physical operation within the taxing state. A previous case had resulted in a rule that the state could only compel the business to collect the tax if it was located in the state. This of course created an incentive for buyers to obtain products from out of state sellers to bypass the tax. Yes, Florida has a form you are required to fill in if you bought out of state and pay the tax on your own. No one does it.
So South Dakota passed a law requiring internet sellers to collect and remit with several conditions that were designed to lessen the burden on sellers. Only those with sales over a threshold must collect, they only collect a uniform statewide tax, not the local county and city tax and South Dakota will provide for free the software to determine what is and is not taxable.
By a 5-4 vote this law was upheld as constitutional. As usual Kennedy was the deciding vote but an unusual group. All 9 justices felt the old rule was wrong and should be overturned. 5 felt the court should do it, as of course they created the rule in the 90's, while 4 felt Congress should clean up the mess.
A good summary is
HERE
If you are planning a significant internet purchase and hope to avoid sales tax you should act quickly.