I sell products on the internet and I MUST now pay Sales Tax; Do You?

The basic rule is that you don't have to pay sales tax for things delivered to a state where you have no physical presence - no employees or assets, either temporarily or permanently during the year.

What the Supreme Court decision says is that even if you have no physical presence, if you make more than 200 individual sales or more than $100,000 of sales into a specific state during a year, then that state can require that you collect and pay sales tax for that state. Not every state has imposed that rule, but more and more are.

If your operation isn't large enough to make those kinds of sales into an individual states, you don't need to worry about it. If you make those kinds of sales into some states, you don't need to worry about the other states.