"Use Tax" to Your State

https://www.investopedia.com/terms/u/use-tax.asp

When you buy things within a state, you have to pay sales tax, which is collected by the merchant who sold you the item.  This is common knowledge. 

However, it is lesser known that when you buy merchendise from a place out of the state, and have the merchendise delivered to your home, you have to pay your home state "use tax", which is at the same rate as the sales tax. 

The out of state merchant is not under the jurisdiction of your state, therefore they are not responsible to collect state sales tax from you.