In most tax jurisdictions they call this a "Use Tax". In theory here in Washington you're supposed to file that with the state annually/quarterly/monthly/whatev

In most tax jurisdictions they call this a "Use Tax". In theory here in Washington you're supposed to file that with the state annually/quarterly/monthly/whatever interval they set for you, but in practice no individual actually does. Businesses that remit sales tax to the state do have a field on the form to include their own use tax as well.