We charge sales tax in states where we are legally required to charge and pay tax*.
In June 2018, in a landmark decision, the U.S. Supreme Court overturned an earlier precedent, ruling that states can collect sales taxes from online retailers. As a result, we are legally required to charge sales tax in states where we have met or exceeded a certain threshold set by the state; have a physical presence (called a "nexus"); or are in states where certain business activities (such as personnel, inventory, affiliate, drop-shipping relationship, etc.) also create a sales tax nexus.
As a result, sales tax will soon be collected everywhere, whether you buy online or at a brick and mortar store.
*Applicable rates vary per location for State and local taxes.